Clothing Comfort

1

Introduction to clothing comfort

1.1

Need and selection of clothing

The basic needs of human are food, clothing and shelter. After fulfilling the first need of food, a person looks for the second important need, i.e. clothing. In the present day society, we expect much more from clothing than to satisfy our basic need. In most societies the clothing is for the purpose of expressing wealth, status, occupation, age, occasion, gender, etc [1]. There are various factors which influence the selection of clothing type. Figure 1.1 illustrates the important factors which influence the selection of clothing. It is evident from Figure 1.1 that the factors which influence the selection of clothing can be divided broadly into four major groups, i.e. social factor, economic factor, environmental factor and physical factor. All these factors play significant roles in selection of clothing of a person.

The social factors include the place where a person lives (urban or rural area), cultural background of person, gender, occupation, occasion, social status, etc. Depending on the place where a person lives, the clothing pattern changes. In urban area, due to close cultural interactions between the various sections of people, the clothing pattern becomes more cosmopolitan in nature. But on the other hand the rural clothing is more influenced by the regional factors. Similarly, clothing is also influenced by cultural background and upbringing of a person. The upbringing influences the taste of a person toward the clothing significantly. The modern society does not believe in gender biasness and strongly oppose this. But, are we ready to accept this to be applied while selecting clothing? Except few exceptions, we are still comfortable in maintaining differences in male and female clothing. In some cases a person selects his clothing depending on the occupational requirement. For example, one can easily make out the difference between a police and a common man depending on his clothing, or in a hospital a nurse can be easily identified based on her clothing. We generally prefer to wear different clothing depending on the occasion, namely formal wear, casual wear, etc. A person generally prefers

Social status Climatic condition Protection from extreme conditions Unusual places (deep sea, space, etc.) Age of a person Health condition of a person Physical structure of body Thermo-physiological responses of body Activity level Factors for clothing selection

Physiological factors Social factors Environmental

factors Economic factors Socio-economic condition Economic status of an individual Availability of technology / raw materials Rural / Urban Cultural

background Gender Occupation Occasion

1.1 Factors affecting the clothing selection.

to wear formal clothing in office, but the same person prefers casual wear in leisure trip. It is also very common that a person tries to show his social status through clothing, this trend prevails in every society since the beginning of the civilization. The kings always tried to differentiate themselves from the common man by wearing royal clothing.

Among the economic factors the important components are economic condition of society, economic status of individual and availability of technology or raw material. When the economic condition of society changes that also reflects through clothing. It is well-known fact that the general clothing pattern of rich and poor sectors of society differs and it is obvious. This is also true for individual. Each individual selects clothing

depending on the affordability. Person also selects clothing to show his economic status. The availability of a particular type of clothing depends mainly on the availability of technology and raw materials. These two factors are directly or indirectly dependent on the economic situation and affordability of the society.

The environmental factors include climatic conditions (too cold, too hot, raining, chilled wind, etc.), protection from extreme environment, unusual places (space or under water), etc. Depending on the environmental conditions the clothing need changes. Here, the performance factors are the dominating parameters. One requires different clothing for different climatic conditions. A person, going to extreme cold place, will definitely like to protect himself from extreme cold by wearing extreme cold protecting clothing. But, the same person will not use the same clothing in normal environment. Depending on the climatic temperature the garments are broadly divided into two categories, namely winter wear and summer wear. Similarly, in rainy days we require clothing which is waterproof. Clothing pattern also changes depending on the environmental threat, like explosives, poisons, biological attacks, fire, radioactive or ultraviolet rays, etc. Clothing also has to withstand falling and flying objects in certain circumstances. Depending on the needs of unusual places, like deep under sea, space etc., the type of clothing changes. In these places the special type clothing are required for protection and specific performance.

The last and very important factor is physical conditions of a person, which include age, condition of health of person, body structure, physiological response of body, activity level, etc. The clothing pattern changes with the age of person due to the psychological and physiological changes with time. A child needs different type of clothing than an aged person. Similarly the clothing need also changes with the physical health of a person. Someone with specific problem with a particular fibre, like allergy, irritation, would like to avoid wearing that particular clothing made with these fibres. Clothing selection also depends on the physical built of body, i.e. whether fat or thin, tall or short, etc. Person with special physical need may require specific clothing. Physiological response of body varies widely from person to person and so does the clothing need. In a given environmental condition a particular person may feel more cold or heat or sweat than others. This is due to the fact that the thermo-physiological responses are different for different persons. The selection of clothing also depends on the level of activity of a person. Under heavy activity the human body generates more heat and sweat. The clothing, he wears, should be able to dissipate and transmit the heat and sweat quickly to keep the body heat under control. A sports person needs special sportswear depending on the type of sports or a worker needs specific work wear depending on his activity. People in challenging activities and sports could

use smart clothing, that is, clothing that can sense the wearer’s condition or situation and, in turn, modify its own structure to protect him or her, for example to keep the body warm or cool.

A very well-known proverb says that “There is no such thing as bad weather, only bad clothing”. Textiles always have played important roles in well-being of a human being by protecting it from different adverse environmental conditions and making him feel comfortable. Comfort characteristic is an important functionality of clothing. Human thermo-physiological comfort is associated with the thermal balance of human body, which is highly dependent on metabolism rate, physical activities, ambient temperature, and thermal and moisture transmission behaviour of the worn clothing [2]. Clothing creates a microclimate between the skin and the environment, which supports the body’s thermoregulatory system to keep its temperature within a safe range, even when the external environment temperature and humidity changes to quite an extent.

1.2

Components of clothing comfort

Comfort is one of the most important aspects of clothing. Many attempts have been made to define comfort, but a satisfactory definition is yet to be obtained [3]. Comfort has been defined by many researchers in different ways [4–6].

● Comfort is influenced by the physiological reaction of the wearer.

● Comfort is temperature regulation of the body.

● Comfort is the absence of unpleasantness or discomfort.

● Comfort is a state of pleasant psychological, physiological and physical harmony between a human being and the environment. All three aspects are equally important, since people feel uncomfortable if any one of them is absent.

So, to know about the comfort characteristics of any particular fabric or clothing, it is required to determine the different properties of the fabric which have direct effects on the comfort.

Broadly there are four basic elements of clothing comfort, namely thermo-physiological aspect, sensorial or tactile aspect, physiological aspect and fitting comfort. The thermo-physiological comfort concerns about the heat and moisture transmission characteristics through clothing, i.e. transmission of heat, air, and moisture (liquid and vapour). The sensorial or tactile comfort is related with the mechanical contact of the fabric with skin, i.e. how a fabric or garment feels when it is worn next to the skin. These are fabric handle or feel, softness, fullness, warm–cool touch, static charge generation, flexing, pricking, itching, etc. The physiological comfort

depends on the aesthetic properties of fabric, i.e. drape, luster, colour, crease, pilling, staining, etc. The fitting comfort deals with the size and fit of clothing.

All the above comfort aspects are strongly correlated between them. In clothing comfort, the most important factor is the movement of heat and moisture (liquid and vapour) through clothing to maintain the thermal equilibrium between human body and the environment.

According to Goldman [7] there are four primary factors in clothing comfort, i.e. function, feel, fit and fashion. The function related to clothing comfort parameters are thermal and moisture (liquid and vapour) transmission, water absorbency, drying behaviour, etc. The thermal transmission is a linear function of fabric thickness and relatively independent of fibre characteristics. Thus the thermal transmission can be controlled by the modification of yarn and fabric structures. Moisture vapour permeability also controls thermal characteristics by evaporative cooling phenomenon. The water transmission in liquid form, i.e. wicking, depends mainly on the type of fibre, weave structure of fabric and the finishes applied to the fabrics. The absorbency of water depends on fibre type, finishes, weave and design of fabric. Although the wicking is important, the amount of liquid that can be blotted away from the skin is also very important. The drying behaviour depends on the type of fibre, fabric and design of fabric. It is important because the ability of the body heat to rapidly dry clothing and restore insulation is a critical factor for survival.

The clothing comfort related to feel are broadly divided into two distinct areas, namely the feel of clothing when held between the thumb and the fingers and the feel of clothing by the wearer when worn in contact with skin. Fit may incorporate factors from fashion, including concepts that may be diametrically opposed to comfort [7]. The clothing fashion is related with the psychological comfort.

1.3

Clothing comfort and wearer’s attitude

Comfort and satisfaction with clothing are influenced by both characteristics of clothing as well as by attitudinal and psychological perceptions of the wearer. The clothing characteristics include the physical characteristics of the fibres and materials from which the clothing is made, its tactile characteristics, design features of the clothing, brand labels, information on fabric/garment care, price, etc [8]. The wearer ’s attitudes towards clothing are influenced by the sensory attributes of the clothing (softness/harshness, warm/cool touch etc.), serviceability characteristic (e.g., durability, creasing, pilling) and most importantly by its expected comfort and satisfaction related attributes.

These attitudes may be gathered either through prior experiences with the exactly same or similar type of clothing, or from information obtained about the clothing through interpersonal, advertising or retail channels. These attitudes toward either fabrics or items of clothing can significantly affect the actual physiological comfort and other performance properties of the clothing and can become the primary determinant of consumer behaviour through their influence on behavioural intentions [9–11]. A large number of studies have been reported on attitudes toward clothing [12–15].

DeLong et al. [12] in their study to evaluate the consumer response to apparels asked consumers to complete the sentence “When I think about sweaters, I think about” without presenting any fabric samples or items of clothing. They performed a content analysis of the words that consumers used in order to assess the factors underlying the concept of “sweater”. Byrne et al. [13], in their perception study on fibre types and end use, used semantic differential grids to study consumer attitudes toward silk, cotton, polyester and nylon for use in sport shirts and undershirts. They have concluded that the consumer attitudes toward the names of different fabrics were distinct and that the intended end-use greatly influenced perceptions of the adequacy of the fabric. During the study on consumer preferences for natural, synthetic and blended fibres, Forsythe and Thomas [14] observed that consumers have well-defined attitudes toward fibres and, with the exception of polyester/cotton blends, these attitudes are consistent across demographic variables. The attitudes of consumer about fabrics and clothing can be reliably assessed with appropriate psychometric techniques applied to fabric or clothing names.

Conjoint analysis technique is widely used by researcher for assessing consumer attitudes toward clothing. This technique deals with the factors related to the consumer attitudes and behavioural intentions by using multi-attribute choice alternatives within a specified experimental design [8, 15, 16]. Using this technique, a survey had been conducted where consumers are given a large set of multi-attribute choice alternatives. Consumers choose or rate each combination of product variables on attitudinal or behavioural dimensions of interest. The product attributes are the dependent variable and by varying the attributes and their levels according to a statistically determined experimental design, conjoint analysis enables the researcher to “work backwards” from the choices/ ratings to uncover the relative importance of each factor to the consumer’s decision process. Conjoint analysis has been used in clothing research to study the relative importance of attributes related to the aesthetic perceptions of garments [17].

1.4

Human–clothing interactions

1.4.1

Clothing as thermal barrier

Hindrance to the release of body heat

Fourt and Hollies [18] have described the clothing system as “a quasi-physiological system interacting with the body”. This means the relationship between human body and clothing is a two-way process. Both the clothing and the wearer perform their specific activities for others. The clothing protects the wearer from the environmental hazards for which it has been designed, whether they are heat, cold, fire, toxic agents or any other thing. At the same time the clothing does some adverse things to the wearer, e.g. by unwanted thermal insulation when it is not required, or by hindering the free evaporation of sweat from skin. Presence of clothing layer(s) prevents the efficient evaporative cooling of human body, which is his sole defence against severe heat. Thus the wearer faces the unbearable and dangerous conditions when he or she works near fire, like overheating, dehydration, and sometime may also collapses.

In normal conditions, without any activity, the metabolic heat produced by a normal person is nearly about 80 watts (same as an electric light bulb!) and in the condition of high activity it can rapidly rise to more than a kilowatt [19]. So, the human body requires an effective cooling system, and physiological system of the body provides this cooling effect. This metabolic heat load, mainly during high activity, poses a consistent threat of overheating and the presence of clothing makes the threat even worse. During high activity in extremely hot environment, e.g. worker in furnace, firefighter, etc. gains hundreds of watts more from the surroundings in addition to the metabolic heat generation. Sweating, which is an excellent mechanism for cooling the skin by evaporating water from it, is the only mechanism to reduce these great heat loads. On the other hand, the excessive sweating may also results dehydration. During high activity condition, in hot environment, a normal person can release sweat at the rate of about 1 litre/hour. There are various linked mechanisms within the human–clothing system which are essential to maintain the correct body temperature and the failure of this link of heat transfer in any form causes increase in body temperature and the person may feel sick or dizzy. The most important mechanisms for effective heat transmission are:

● all the metabolic heat produced should be carried to the inner body surface (inner layer of skin) by the effective circulation of sweat;

● the skin should be able to generate the necessary amount of sweat; ● the generated sweat should get transmitted effectively (in liquid as

One cannot adjust or change the first two mechanisms, but can definitely control the third mechanism by proper clothing. When someone wears excess number of clothing than what is required, he may feel overstressed or overheated with normal activity.

Helps to retain body heat

Except very hot environmental conditions and at very high activity levels, most of the environmental temperatures are below the human body temperature and clothing is required to hinder the flow of body heat to the atmosphere. So, in all these environmental conditions the heat flows out from the human body to the atmosphere due to the temperature difference, i.e. human body temperature is higher than the environment. In normal room temperature, i.e. approximately 27±2°C, the wearer requires minimum clothing layers to maintain the heat balance. The wearer does not require too much thermal insulation in clothing as the temperature difference between skin and the normal environment is low. The heat, generated in the body, gets transmitted slowly through the clothing and the open body surfaces (hands, arms, face, palms, etc.). As the temperature of the atmosphere drops further (say below 10°C) the rate of heat loss from body to atmosphere increases rapidly and the wearer feels cold due to thermal imbalance. The best and easiest way to prevent this body heat loss is to have certain insulating layer around the body, and that is done by wearing some additional layers of clothing (which also provide insulating still air layer). Under this condition, loss of body heat through clothing drops significantly and little amount of heat loss still takes place through some opening of body surface. In extreme cold conditions (say below –20°C) the loss of body heat is prevented by enhancing the thermal insulation of clothing and covering all the body parts.

1.4.2

Mechanisms of enhancement of body heat

release

The symptoms of overheating or overstress due to excess number of clothing rapidly disappear when the excess clothing is removed. The transmission of body heat through clothing ensemble changes automatically by different mechanisms. Activity of the wearer influences the heat transmission characteristics of clothing. As soon as the wearer starts moving or walking or running the thermal insulation of clothing reduces because of a combination of forced air circulation between and through the layers of clothing. This reduction in thermal transmission is further enhanced by the typical bellows effect at various openings and also due to movement

the thermal insulation of the surrounding air reduces. During activity the clothing gets wet from sweat which also causes the drop in the thermal insulation. This automatic reduction in thermal insulation of clothing during activity level may not be always sufficient and in those cases the wearer becomes over-heated and sweats. This is due to the fact that the clothing layers actually hinder evaporation of sweat. Majority of the generated sweat wets the clothing in normal environment or in cold environment condenses in the outer layers. In either case the sweat removes less heat from the body than it does when it is able to evaporate from the skin, and additional sweat therefore has to be secreted to maintain the heat balance. Consequently the wearer is too hot while he is active, and when he later rests he becomes chilled because of the reduced insulation of wet clothing and the continuing evaporation of water from it [19]. The over-heating of body can also be reduced by proper clothing design, i.e. by providing effective ventilation in the clothing. The changes in clothing design may be effected by:

(i) creating openings, to allow natural convection by chimney effect, at various places in the clothing, e.g. neck, wrists, ankle and waist. (ii) designing loose fit clothing to have free convection of air and free

interchange with outside air by means of a bellows effect.

(iii) providing full-length zippers in the clothing for specific applications. (iv) avoiding the use of impermeable materials, whenever possible, can

further facilitate evaporative cooling.

1.4.3 Multilayer clothing system

Most of the performance clothing assemblies are generally not a single layer system. These generally consist of a number of layers and each layer performs its specific function. These layers are generally of three types, i.e. inner layer, middle layer(s) and outer layer. A clothing ensemble that should function with high requirements to comfort and protection must be put together methodically from the inside out [20]. Figure 1.2 shows the typical functions of individual layers of a three layer clothing system, where the inner layer is generally an underwear which performs mainly the sweat absorption, direct cooling of the skin, transmission and tactile functions; the middle layers are generally shirt or sweater which helps still-air entrapment to provide insulation, transmission etc.; and the outer is primarily a shell layer for protection from extreme environmental factors, like rain, wind, chemical, heat, radiation, etc.

1.5

Understanding clothing comfort

1.5.1

Need and consumer trends

The basic and universal need of consumers in clothing is comfort and they look for good feel and comfort when they buy clothing and other textile materials. Clothing is very important in our life that we use everyday to obtain physiological and psychological comfort and also to ensure physical conditions around our body suitable for survival. Therefore, it is extremely important for the survival of human beings and improvement of the quality of our life to have good understanding of the fundamentals of clothing comfort. From the viewpoint of the manufacturers of clothing and textile materials, understanding of clothing comfort has substantial financial implications in the effort to satisfy the needs and wants of consumers in order to obtain sustainable competitive advantages in modern consumer markets. Consumer always expects some additional functional qualities from the clothes they purchase. Clothing is manufactured in a wide range of thermal, tactile and physical properties to meet consumer needs. Depending on the needs and expectations of the consumers, the clothing and textile manufacturers provide wide range of options to enhance human comfort. For example, clothing made from blends and natural fibres are preferred to man-made fibres for all comfort attributes except smoothness, or woven fabrics are preferred to knits for smoothness, thickness and openness. To understand the basics of clothing comfort, sensory tools as well as the equipments to evaluate the comfort related characteristics of textile materials have been developed. Large number of studies has been carried out and many equipment are developed in the textile and clothing area such as mechanical, thermal and surface testing, so as to evaluate the related physical properties, but the links between measurement and the consumer feeling of comfort are still difficult to establish.

1.2 Three-layer clothing system [21].

Thermal protection Water repellecny Wind proof Outer layer Middle layer Inner layer Heat or Sweat (liquid or vapour)

Consumers want everything from the clothing, i.e. it should look good, feel good, perform well, would like their clothing to match with their chosen attitudes, roles and images. Consumers are now allowing touch, smell, intuition, and emotion to influence their decision on clothing selection more than their aesthetic sense. As a result, great importance is being attributed to the wearing experience and thus comfort is being reinforced as a key parameter in clothing. It is also true that requirements of consumers on comfort changes with products and situations. Clearly, understanding and satisfying the needs of consumer towards clothing products are crucial for the long-term survival and growth of clothing and textile demand. Understanding and enhancement of clothing comfort is definitely one of the important issues.

1.5.2

Scientific approaches

To have proper understanding of the clothing comfort and to predict comfort performance of clothing during wear, one needs integrated scientific knowledge of physics, physiology, neurophysiology, and psychology of comfort. In long-term perspective, it is very important to have proper knowledge on clothing comfort to improve the quality of life and the survival of human beings. The clothing and textile industries should take necessary initiative in this area to achieve market leadership. Researchers identified the psychological sensory attributes what consumer desire, which is correlated with the technical parameters of clothing through psychophysical perceptual trials. The clothing can be developed with specified technical parameters to achieve certain level of psychophysical comfort. Li [22] reported that there are five levels of understanding clothing comfort. The important steps for scientific understanding of clothing comfort are market research, wear trials, objective evaluation of clothing characteristics and objective evaluation of fabric characteristics. The market research is generally carried out by identification of target group, personal interviews and consumer surveys to gather market information on the products. The wear trials can be conducted either in the field in which the clothing are used or in climatic chambers for psychological sensory study, consumer focus group study and subjective evaluation of clothing. The objective evaluation of clothing characteristics, e.g. thermal and moisture transmission are generally done either on human subjects or thermal manikins. The objective evaluation of fabric characteristics are carried out by testing transmission (moisture, heat), handle, tactile and aesthetic characteristics of fabrics. The information on clothing comfort requirements should flow from customer to technical specifications of fabrics and clothing to have a new product that can satisfy the requirements of consumers. On the other hand, one can predict the consumer acceptability of particular clothing by proper understanding of

fabric and clothing characteristics, physical and psychophysical mechanisms. Using statistical and mathematical tools one can easily optimize the clothing parameters as per the identified consumer’s requirements even before actual production.

References

1. COATES J. F., ‘From my perspective: The future of clothing’, Technological Forecasting & Social Change 72, 101–110, 2005.

2. OLSCHEWSKIH. and BRUCK K., ‘Cardiovascular and muscular factors related to exercise after pre-cooling’, J. Appl. Physiol. 64, 803–811, 1988.

3. SLATERK., ‘Comfort properties of textiles’, Text. Prog. 9(4), 1–42, 1977. 4. HATCHK. L., Textile Science, West Publishing Company, New York, 1993. 5. SLATERK., Human Comfort, Thomas Springfield, Illinois, 1985.

6. SLATERK., ‘The assessment of comfort’, J. Text. Inst., 77, 157–171, 1986. 7. GOLDMANR. F., ‘The four ‘Fs’ of clothing comfort’, Elsevier Ergonomics Book

Series: Environmental Ergonomics - The Ergonomics of Human Comfort, Health and Performance in the Thermal Environment 3, 315–319, 2005.

8. SCHUTZHOWARD G., CARDELLO ARMANDV. and WINTERHALTERC., ‘Perceptions of fiber and fabric uses and the factors contributing to military clothing comfort and satisfaction’, Textile Res. J. 75(3), 223–232, 2005.

9. SMITHJ., ‘Perceived comfort’, Text. Horiz. 9, 44–45, 1986.

10. SHIMS. and DRAKEM. F., ‘Consumer intention to purchase apparel by mail order: beliefs, attitude, and decision process variables’, Cloth. Textiles Res. J. 9(1), 18–26, 1990.

11. WITTER B. S. and NOEL C., ‘Apparel advertising: a study in consumer attitude change, cloth’, Textile Res. J. 3(1), 34–40, 1984–85.

12. DELONG M. R., MINSHALL B. C. and LARNTZ K., ‘Use of schema for evaluating consumer response to an apparel product’, Cloth. Textiles Res. J. 5, 17–26, 1986.

13. BYRNEM. S., GARDNER, A. D. W. and FRITZ, A. M., ‘Fiber types and end-uses: A perceptual study’, J. Textile Inst. 84(2), 275–288, 1993.

14. FORSYTHES. M. and THOMAS, J. B., ‘Natural, synthetic and blended fabric contents: an investigation of consumer preferences and perceptions’, Cloth. Textiles Res. J., 8(3) 60–64, 1989.

15. GREENP. E. and SRINIVASAN, V., ‘Conjoint analysis in consumer research: issues and outlook’, J. Customer Res., 5 103–124, 1978.

16. GREENP. E. and SRINIVASAN, V., ‘A general approach to product design optimization via conjoint analysis’, J. Marketing 45, 17–37, 1978.

17. ECKMANM., ‘Attractiveness of men’s suits: the effect of aesthetic attributes and consumer characteristics’, Cloth. Textiles Res. J. 15 (4), 193–202, 1997. 18. FOURTL. and HOLLIESN. R. S., Clothing: Comfort and Function, Dekker, New

York, 1970.

19. BUDDG. M., ‘Clothing physiology’, Fire Safety Journal 4, 77–81, 1981. 20. RUTHN., Work clothing, International Journal of Industrial Ergonomics, 7, 77–

85, 1991.

21. DASA., Objective evaluation of comfort characteristics of textiles, Seminar on comfort in textiles, Department of Textile Technology, IIT Delhi, October 16, 2004. 22. LIY., The science of clothing comfort, Textile Progress 31(1/2), 2001.

13

Psychology and comfort

2.1

Psycho-physiological factors of clothing

comfort

The physiological factors of human body for expressing the human comfort are average skin temperature, degree of skin wetness (indicated by electrical conductivity at the body surface), rate of sweating, the amount of sweat, sweat absorbed by clothing, and rate of heart beat. It is important to correlate all the physiological parameters with contributing psychological factors to predict the perceptions of comfort. Thermal effects contribute extensively to the ‘comfort’ of an individual, complex physiological and psychological factors collectively play an important role in defining this complex quality with reference to clothing [1]. In fact, clothing comfort is the psychological feeling of wearer who wears the clothing under different environmental conditions. The factors influencing the clothing comfort sensations of wearer can be divided broadly into three groups: (i) physical factors (deals with the human–clothing–environment system); (ii) psycho-physiological factors of the wearer; and (iii) psychological filters of the brain. The comfort status of wearer depends on all these factors and their complex interactions and synchronizations.

Figure 2.1 shows the interrelationships between the important physical and physiological factors those control the clothing comfort. The figure illustrates the process of how the subjective perception of overall comfort is formulated. The physical processes provide different signals or stimuli (e.g., warm/cool, touch, prick, pressure, wetness, etc.) to the sensory organs of the human body. The human body receives all these stimuli and subsequently generates neurophysiologic impulses. The neurophysiologic impulses are then send to the brain to take corrective actions to adjust the sweating rate, blood flow, and sometimes heat production, shivering, etc. [2]. The brain, after receiving the sensory impulses, processes all these impulses to generate the human subjective perception of various individual sensations, and further evaluate and weigh them based on the past experiences. The processes of evaluation and weighing are influenced by

many factors such as physical, environmental, social, cultural, etc. The clothing comfort is a human psychological perception related with clothing ensemble, which is an outcome of complex linkages between individual sensory stimuli received by brain, evaluation and weighing of all these stimuli to formulate subjective perception of overall comfort based on wear experience.

2.1 Important physical and physiological factors controlling the clothing comfort.

2.1.1

Psychological perceptions of clothing comfort

The wearers consider the comfort as one of the most important attributes in their clothing ensembles, so there is a need to develop an in-depth scientific understanding of the psychological perception of clothing comfort sensations. The physical comfort is greatly influenced by tactile and thermal sensations arising from contact between skin and the immediate environment [3]. Comfort may be defined as pleasant state of physiological, psychological and physical harmony between a human being and the environment [4]. Comfort can also be defined as a holistic concept, which is a state of multiple interactions of physical, physiological, and psychological factors [5]. All these definitions only identify the factors influencing the human psychological perceptions. Wong et al. [6] developed a linear model based on artificial neural network predictions using three major factors which affect the comfort perceptions, namely moisture related factor, tactile sensations and thermal-fit comfort, and their relative weights

to predict overall comfort perceptions. They have developed feed-forward back-propagation neural network models to predict an overall comfort perception from ten individual sensory perceptions (clammy, clingy, damp, sticky, heavy, prickly, scratchy, fit, breathable and thermal). They have reported a good agreement between predicted and actual clothing comfort perceptions, which indicated that the neural network is an effective technique for modelling the psychological perceptions of clothing sensory comfort. They have further reported that the functions and interrelationships of individual sensory perceptions and comfort are unknown.

2.1.2

Sensory perceptions of clothing comfort

Different types of sensations generated from clothing ensemble depend mainly on the various combinations of type of clothing, type and level of activities and the environmental conditions experienced by the wearer during the activities. The most common clothing comfort related sensory attributes are thermal, moisture, tactile, hand, and aesthetic experiences. The experts in the field of sensory attributes can easily identify the difference between the above attributes and suggest accordingly. But, it is very important to identify some commonly recognized comfort attributes of clothing among ordinary wearers, and what they are if they exist. When the level of human activity or the temperature and humidity of microclimate change the changes in various sensory perceptions, like warmth, chilliness, scratchiness, dampness etc., can be very easily detected [7]. Strong sensations can also be experienced, both indoors and outdoors, when mild or heavy sweating occurred, and during modest excursions of warming or chilling following the inception of sweating. There are many attributes which describe the clothing comfort sensory perceptions of human. Some of the important attributes are loose or tight, heavy or light, stiff or pliable, sticky or non-sticky, absorbent or non- absorbent, cold or warm, pleasant or clammy, dry or damp, pricky or non-pricky, rough or smooth and scratchy or non-scratchy, etc. Some of these attributes do not give useful contribution in prediction of clothing comforts. So, most important and established attributes for subjective evaluation of sensory perceptions of clothing comfort are course–fine, rough–smooth, stiff–pliable, harsh–soft, cool– warm, hard–soft, and rustle–quiet, for expressing sensorial comfort. In developing methodology for evaluation of fabric handle, Kawabata [8] generated sensory attributes by letting a panel of expert judges (the Hand Evaluation and Standardization Committee) judge the fabric handle and asking them the reasons for their decisions. They identified terms such as KOSHI (stiffness), NUMERI (smoothness), and SHARI (crispness) as ‘primary hand’ expressions.

The investigation on physiological sensory responses to clothing, of consumers living in different countries, revealed that the ratings of most of the sensory attributes are significantly different between three types of clothing, i.e. summer wear, winter wear, and sportswear. No significant differences in rating of the sensory descriptors were found between male and female respondents. The physiological sensory responses to clothing which were considered in the study are snug, loose, stiff, lightweight, staticky, non-absorbent, sticky, heavy, cold, damp, clammy, clingy, rough, cool, hot, soft, warm, wet, prickly, itchy, chill, sultry, tickling, and raggy [2]. The wearers themselves know best and they are capable of making objective, quantitative and repeatable assessments of their sensations of their clothing. Therefore, sensory attributes should come from the wearers instead of experts or researchers.

2.2

Psychophysics and clothing comfort

2.2.1

Laws of psychophysics

Fechner, in 1860, originated psychophysics to describe the mathematical relationship between the conscious experience of a sensation and an external physical attributes [9]. According to his theory, if one knows the mathematical form of the psychophysical relation between a physical attribute and its corresponding sensation, he can measure psychological attributes by measuring their physical factors. Therefore, psychophysics is about the quantification of the strength of internal sensations, which can be broadly defined as the quantification of sensory experience. The strength of internal sensations has two aspects of indication, i.e. (i) the assessment of human powers of signal identification and sensory discrimination, and (ii) the calibration of subjectively perceived intensities and other parameters of stimulation.

Weber, in 1834, [10] proposed that the threshold (i.e. the just noticeable difference) of stimulus (ΔS_p) are proportional to the magnitude of stimulus

S_p. This is known as Weber’s law and can be expressed as:

S_p/S_p= K (1)

where K is a constant indicating the power of a human being to detect signals and discriminate sensations. This law holds good for many stimulus attributes down to about the absolute threshold which is the smallest magnitude of stimulus that can be perceived.

Fechner, in 1860, [9, 10] proposed using “just noticeable deference” as a unit to measure internal sensation. Fechner assumed that sensation R_s increases as the logarithm of physical stimulus magnitude S_p; this is called Fechner’s law and can be described as:

R_s= K´logSp (2) where K´ is the constant determined by the stimulus threshold which represents the lowest physical value evoking sensation and the deferential threshold providing a subjective unit of sensory intensity. This law states that sensation increases in arithmetic steps as the physical stimulus is increased in logarithmic steps. Both Fechner’s law and Weber’s law of psychophysics are related to each other.

Stevens, in 1953, [10] developed a method of estimation of the relationship between subjectively perceived intensity and physical stimulus strength. This method was applied to a large number of different stimulus attributes. The results from each stimulus attribute generally follow the following relationship,

R_s= aS_pb ₍₃₎

where, ‘a’ is a scale factor and ‘b’ an exponent characteristics of the attribute. This equation is known as Stevens’ power law.

All these laws of psychophysics indicate that there are fundamental differences between the physical stimulus and the sensation that one experiences. Weber’s law and Fechner’s law play some fundamental role in sensory discrimination in terms of the ability to distinguish one stimulus from another, but fail to provide a basis for measuring sensation. Stevens’ law proposes a power relation between physical stimulus magnitude and internal sensation which provides a ‘direct’ measurement of sensation in sensory judgment process.

2.2.2

Types of psychophysical scaling

Psychological scaling is a process of assigning numbers to characteristics of objects or events, according to rules which reflects some aspects of reality. Psychological scaling has been widely used in marketing research to obtain consumers opinions and study their attitudes and preferences. Assigning numbers does not always correspond to the real numbers that are obtained from objective measurement in physical means. The numbers cannot necessarily be added, subtracted, divided or multiplied. The numbers are used as a symbol to represent certain characteristics and the rules specifying how numbers are assigned to the characteristics to measure. These rules may be arbitrary and changes as per the specific condition.

The rules governing how to assign numbers constitute the essential criteria defining each scale. There are four types of scale of measurement: nominal scale, ordinal scale, interval scale and ratio scale [11]. Moving from nominal scale to ratio scales, the rules become more complex and the kinds of arithmetic operations for which the numbers can be used are

increased. Each scale exhibits symmetries and hence corresponds to a type of symmetry group [12]. In fact, the four scales correspond to a descending sequence of subgroups, e.g. the group for the nominal scale containing the group for the next scale, i.e. the ordinal scale. Similarly, the group for the ordinal scale contains the group for the interval scale, and the group for the interval scale contains the group for the ratio scale. In other words, the symmetries which are members of the set corresponding to the ratio scale are also members of the set corresponding to the interval scale although the latter contains additional symmetries as well, and so on, the set corresponding to the nominal scale having the greatest number of symmetries as members [13].

Nominal scales consist of numbers used to categorize objects. A nominal number serves as a label for a class category. In a nominal scale, items are sorted into classes with no quantitative information conveyed. Numbers may be used in a nominal scale, but they are only used to indicate group membership, e.g., the numbers on the jersey of a player in a hockey team or one can assign 0 to male and 1 to female. The number 1 does not imply superior position to number 0 or number on the jersey of a player generally does not indicate the performance of player. The rules for nominal scales are that all numbers of a class have the equal value. The only arithmetic operation that can be performed on nominal data is the count in each category. Nominal numbers cannot be added, subtracted, multiplied and divided. The nominal scales only distinguish the objects or events on the scale from things that are not on it. Due to its high degree of symmetry, it conveys little information and is hence the weakest form of measurement. For example, grading the students only in the form of pass or fail does not convey much information about student performance than assigning grades or exact percentile.

Ordinal scales comprise numbers or other symbols used to rank the events or objects according to their characteristics and their relative position in the characteristics. Ordinal data indicate the relative position of objects on certain characteristics scales but not the magnitude of the differences between the objects. A mode or median may be used, but not a mean. Non-parametric statistics can be applied to ordinal data. Some of the symmetries in nominal scales disappear during the shifting of events or objects from nominal to ordinal scales. This is because the ordinal scale is less symmetrical than a nominal scale. For example, generally the top person in an organization gets highest salary and the salary reduces according to the hierarchy in the organization. But as long as the hierarchy is preserved, there is no social significance in varying the salary in each level. Hence, there are symmetries here as well, transformations which would make no social difference. But there is less symmetry here than in nominal scales,

since some transformations that would not socially matter in ordinal scales do matter in nominal. For example, giving more salary to manager than the president would be forbidden, or it would indicate a change in status. The transition from ordinal scale to interval scale results in a reduction of symmetries. In the interval scales the numbers are used to rank the objects or events in such a way that numerically equal distances on the interval scale represent equal distances in the characteristics of the objects or event being measured. But both zero and their unit of measurement are not fixed and are arbitrary. Therefore, interval data can indicate both relative position of objects and the magnitudes of differences between the objects on the characteristics being measured. The entire range of statistics can be applied to interval scales. On an interval scale, one unit represents the same magnitude as any other. For example, in Box and Behnken [14] three-factors and three-level model the factors (independent variables) are coded with –1, 0 and +1 for their three levels. In the actual data the intervals in the factors are numerically same. Another example is the measurement of temperature in centigrade scale. One degree centigrade is warmer than 0°C degrees to the same extent as 2°C is warmer than 1°C. Fiske [11] stated that “Equality matching relationships resemble an interval scale in that people can not only specify who owes what to whom, but also how much they owe”. On the basis of ordinal scale, people keep track of imbalances or differences between each other and try to maintain balance. Equality, following particular turn, strict reciprocity is maintained strictly. Examples are voting, games that involve equal turn-taking, and so on. There is less symmetry here than in the case of ordinal scale. In interval scale, one must make sure that everyone has the same thing, however, sameness is defined. This degree of precision is lacking in ordinal scale [13].

A ratio scale is exactly like an interval scale, except that it has an absolute 0 point. For example, the kelvin temperature scale has absolute zero point but the centigrade temperature scale measures the freezing point of water defined as zero degrees Celsius and does not have absolute zero scale. Ratio scales represent the numbers used to rank objects such that numerically equal distances on the scale represent equal distances of the characteristics measured and have a meaningful zero. Like interval scales, entire range of statistics can be applied to ratio data. Ten degrees centigrade is not twice as hot as 5°C, but 10 K is twice as hot as 5 K. In ratio scale, people order their interactions according to a system of ratios and proportions such as salary, rents, taxes, etc. This allows each individual or group of like-minded people to decide how to act and evaluate actions according to cost-benefit analysis [13].

All the above four types of psychological scales are important for better understanding of psychology of clothing comfort. The nominal scales

determine quality and have been used for categorization and classification such as gender, age, and place of living. Ordinal scales determine equality and relative position and have been used to obtain the rankings of fabrics or clothing in consideration. The most frequently used scales are the interval scales, which determine equality, relative position, magnitude of differences and have been widely used to obtain the perception of various attributes of clothing. The ratio scales are mainly applicable to the data generated from physical instruments, which determine equality, relative position and magnitude of difference with a meaningful zero.

2.2.3

Psychophysical scaling of clothing comfort

The tactile parameters, like prickliness, fabric itchiness, fabric stiffness, fabric softness, fabric smoothness, roughness, scratchiness, etc., are basically sensory comfort attributes, but the psychological comfort is not a sensory attribute, because it is not associated directly with any single human sense organ. The psychological clothing comfort is characterized by emotion and affection, which is related with the liking towards particular clothing. Thus, there is no underlying physical dimension of the stimulus that varies continuously and is monotonic with the perception of comfort. The same stimulus can generate altogether different comfort responses from different individuals. As a result, it is not possible to define a comfort scale based on physical standards that is valid for all users [15]. In general the clothing comfort is characterized by emotional attributes, so the judgment can be done effectively by untrained consumers instead of experts. This requires a method for psychophysical scaling of clothing comfort that is simple and easy to understand which do not require any training or complex instructions. The ‘category scale’ is the most commonly used subjective scale for rating comfort. This is characterized by a series of verbally and/or number labelled points or descriptive categories, like ‘extremely comfortable’, ‘moderately comfortable’, ‘slightly comfortable’, etc. In this type of scaling, a person can rate his subjective comfort sensations by placing them into one of several descriptive categories. Since less than five categories can result in a loss of discrimination sensitivity, the number of categories is typically around seven to nine, or sometime it can also be more [16, 17]. Due to the simplicity, versatility, and high reliability the ‘category scales’ are widely used for measurement of subjective clothing comfort and other psychological attributes.

Although there are many advantages, still there exist some critical problems associated with the use of ‘category scales’. In case of a numbered category scale, the numbers with equal intervals do not represent equal subjective intervals [18]. In the labelled category scales, subjects attend primarily to the word labels and not to the numbers [19]. In these

cases, unless the verbal labels are chosen on the basis of extensive evaluation process to verify that the differences between ‘slightly comfortable’ and ‘moderately comfortable’ are the same as those between ‘moderately comfortable’ and ‘extremely comfortable’ the scale cannot be considered to be an interval scale, but merely an order of comfort sensation. Another common problem with category scales is that the normal tendency of a person is to avoid the end categories; this is called “category end effect”. This “category end effect” results in seven-point category scales being functionally reduced to five-point scales after eliminating two end points; and similarly the five-point scales is reduced to three-point scales, and so on.

The recent developments in psychophysical methodology that enable better quantification of both the descriptive aspects of tactile sensations and the scaling of the emotional attributes of handle helped the researchers in applying well-established psychophysical approaches to study the sensory and comfort characteristics of clothing. After the development of Kawabata instrumental evaluation systems [8, 20, 21] for measuring low-stress mechanical characteristics of fabrics, it has now become relatively simple to measure many subjective attributes objectively. Combining the psychophysical sensory methodology with the established instrumental methods of fabric characterization now makes it possible to develop better predictive relationships among sensory, instrumental and comfort characteristics of clothing.

2.3

Wear trial techniques

Human being often uses hands to obtain tactile information, but much of the tactile sensations come from parts of the body other than hands. This suggests the necessity of study of the perception of clothing comfort in actual wear situations. Therefore the wear trialing is an important technique for clothing comfort research. Sensory clothing comfort perceptions are primarily associated with skin sensory systems. In addition to this the clothing comfort sensations involve various sensory channels from all the five senses: visual, auditory, smell, taste and touch. A certain type of clothing comfort sensation is generated under certain wear conditions with a particular type of external stimuli and physical activity. The external stimuli (heat, moisture, wind, etc.) and mechanical stimulation from fabric to the skin (softness, scratchy, pricky, etc.) are normally generated under specific combinations of physiological states (e.g. sweating rate), materials used in the clothing, fitness of clothing and environmental conditions (e.g., temperature, humidity and air velocity).

Hollies et al. [22, 23, 25] proposed the wear trial technique to generate reactions of wearer to any perceived discomfort sensations produced by

different climatic conditions, and by alternating sweating and cooling off conditions that might be encountered in actual wear of clothing. In the wear trial experimental technique they also characterized the sensory comfort of clothing, which included a number of components:

(i) Generation of sensory attributes with wearers.

(ii) Selection of particular testing conditions for effective analysis of the perception of various sensations.

(iii) Designing attitude scales in the way of subjective rating sheets to obtain various sensory responses to particular garments. The sheets contain different comfort attributes (e.g., stiff, sticky, non-absorbent, cold, damp, clammy, clingy, rough, scratchy, etc.) at different time interval in particular environmental condition. The comfort intensity was scaled at five different scales, i.e. 1 is totally uncomfortable and 5 is completely comfortable.

(iv) The wear trial was then conducted in controlled environments chambers according to predetermined protocol.

(v) The wearers rated the garments for each comfort attribute separately for different time interval.

(vi) All collected data were analyzed and the results were interpreted. In a recent research study [24] warm and humid climatic conditions were produced using a climatic chamber with precise control of air temperature and humidity. In this study, different varieties of garments were worn with six coverall types. Each test session was made up of five individual evaluation periods, which yielded approximately 900 individual evaluations. Comfort ratings were assessed on all test garments in each of the five rating periods of the protocol. An evaluation form was designed to record ratings of comfort and sensory properties for each of the five periods. The scales used to assess overall comfort, thermal sensation, and contact comfort sensations were recorded. During each evaluation period, wearers were asked to indicate the number, on the designated rating scale, that best described their perceived sensations. The wearers and the garments were precisely weighed before and after completion of the wear trial protocol to estimate the moisture loss from the body, and to determine the amount of moisture accumulated in the test garments. During the wear trial study the overall comfort sensations, thermal sensation and skin contact comfort sensations of garments were rated by the wearers with different terms and scales. The overall comfort sensations were expressed in seven scales, i.e. 1 – Very uncomfortable, 2 – Uncomfortable, 3 – Slightly uncomfortable, 4 – Neither comfortable nor uncomfortable, 5 – Slightly comfortable, 6 – Comfortable and 7 – Very comfortable. Statistical techniques have been adopted for data analysis.

Wong et al. [26] used neural network technique in wear trial to predict the human psychological perceptions of clothing sensory comfort. They have selected twenty-two professional athletes as subjects to take part in the psychological sensory cycling trial. The wear trials were conducted in an environmentally controlled laboratory. Before the trial, athletes were subjected to medical fitness examinations to ensure that they were able to complete the experiment. They have chosen different commercial sportswear in their study. Initially they invited the professional athletes for a pre-trial before the formal trials to obtain training and understanding of the questions and procedures involved. During each trial, each athlete was required to shower upon arriving at the laboratory, then change into a test garment and a pair of nylon shorts, and rest to equilibrium for 20 minutes. During the wear trial the laboratory conditions were controlled at 15°C, 65% RH, and an air velocity varying between 0.15 and 1.50 m/s. At the end of the equilibrium period the athletes were asked to ride ergonomic bikes for 90 minutes under work loads maintaining their heart rates at 70% of their estimated maxima. The athletes were asked to rate the sensory perceptions (e.g., clammy, clingy, sticky, damp, heavy, prickly, scratchy, fit, breathable and thermal) of the sportswear at different time interval, i.e. at the beginning, after 30 minutes, after 60 minutes and after 90 minutes. The ratings by the athletes were subsequently converted into 0–100 scales for all the sensory perceptions except fit and thermal sensations. The fit and thermal sensations were rescaled to the range from -50 to +50 because in these two perceptions the wordings used in the scale’s two ends to describe the perception of fit (from too loose to too tight) and thermal (from too cold to too hot) were different from the other sensory perceptions such as damp (from not at all to extremely). In their study, Wong et al. [26] developed the neural network prediction model on the basis of a feed-forward back-propagation network. The network model consisted of three layers, i.e. input layer, hidden layer and output layer. A good agreement between predicted and actual clothing comfort perceptions have been observed, which proved that the wear trial technique is an effective technique for predicting the psychological perceptions of clothing sensory comfort.

2.4

Psychological aspects of aesthetic comfort

The physical attributes of the human body is directly related to the aesthetic comfort characteristics of clothing. A large number of researchers [27– 32] have studied the complex interplay between clothing aesthetics and body attributes and the human body has been designated as the central element in the aesthetic experience of clothing. The relationships between the aesthetics of clothing and the physical attributes of the body is not the matter of only textile and clothing discipline but many other fields of

research, like physical and demographic attributes affecting aesthetics, social aspect, psychological, cultural aspects that influence the aesthetic experience, etc. The researchers have taken into account of all these factors in their studies on clothing aesthetics.

Human body imaging technique may be adopted in the study of clothing aesthetics. The clothing not only creates a person’s appearance but also provide aesthetic pleasure to the person through the wearing experience. The wearers generally try to achieve the aesthetic pleasure through their clothing by emphasizing certain positive features of their bodies through their clothing and hiding other negative features. Therefore, aesthetic attributes in clothing helps to minimize the differences between cultural beauty concepts and their perceived appearance, which helps to improve self-image and have stronger self-esteem of a person [33].

2.4.1

Evaluation of clothing aesthetics

Clothing comfort related to aesthetics is a complex interrelationship between the following concepts:

● Style of the clothing adopted

● Surface texture of clothing

● Drape of fabric used

● Cover

● Creasing and resilience characteristics of fabrics.

All these concepts are generally described by how they are subjectively perceived by common word pairs used to communicate their values (e.g., thick–thin, rough–smooth, etc.). The physical or transmission characteristics of fabrics, namely mass per unit area, thickness, thread density, air permeability, thermal transmission, wicking, etc., can be easily measured by objective test methods. But, due to significant subjectivity the aesthetic characteristics cannot be measured accurately and there is no standard method of measuring aesthetic characteristics of clothing. The fabric aesthetics is entirely subjective and different people can rate same fabric in different scales based on their own perceptions.

The main problem with the measurement of aesthetic attributes of clothing is to gather useful and consistent information by questioning people about the clothing or fabric. If this is done properly, then the numerical data can be obtained using different mathematical techniques and subjective test methods. The possible steps to measure the fabric aesthetics are [34] as follows:

● Definition of fabric aesthetics in terms of basic elements having the form of common words.

● Identification of a system for selecting rating scales. This system involves questions for subjective measurement of these basic elements.

● Transformation of data from rating scales to numerical definition of

a specific aesthetic property.

By the term ‘aesthetics of clothing’ we generally mean the appearance and handle of fabrics, which are mainly perceived by the senses. It has been already mentioned that the perceptions are relative attributes, i.e. it can be scaled based on their relative position on scales involving contrasts (warm–cool, good–bad, soft–hard, beautiful–ugly). Clothing aesthetic perceptions are the combinations and interrelations of measurable physical data (rigid–flexible, soft–hard) and values, which are psychological factors (good–bad, beautiful–ugly, fashionable–unfashionable). Some terminologies associated with the aesthetics of clothing are really conceptual, for example hand, cover and body do not have value polarity, i.e. they need not be good or bad, desirable or undesirable. Moreover, all these terminologies do not have a simple measurable physical reality. However, sometimes these parameters are defined to represent sense data only. For example, ‘surface texture’ is a fabric parameter which can be measured subjectively, but still this is merely a terminology which represents the skin sensorial as well as visual sensations of fabric. Limiting the meaning in this way often restricts communicative value. The surface texture of fabrics is evaluated in relation to the aesthetic comfort characteristics of clothing. To evaluate is to judge something on a scale that has opposite poles or a gradation. For example, a scale for evaluating comfort concepts is the pain–pleasure polar scale. It is a psycho-physical scale. Aesthetic concepts are not physical attributes. These can be expressed in terms of psycho–cultural scales and can be evaluated on polar scales such as beautiful–ugly, good–bad, etc. The surface texture of a specific type of fabric can be evaluated by the simple polar word scale, like soft– harsh or rough–smooth. It is quite possible that a fabric is aesthetically very beautiful, but painful from the skin sensory comfort point of view. For example, a tweed fabric may be unpleasant to the skin but pleasant to the eye or an aesthetically beautiful winter garment may be thermo-physiologically extremely uncomfortable in warm and humid conditions. The aesthetic character of fabrics is primarily defined by subjective methods. The wearers are asked to evaluate qualities identified by simple word pairs whose meanings can be easily recognized as polar opposite words, like smooth–rough, soft–hard, flexible–rigid. Some of the confusing clothing terms should be avoided in evaluating the fabric aesthetics. For example, for evaluating the drape behaviour of fabric, if one wants to decide the fact that whether the fabric is good or bad the answer will create

confusion. He should know the exact application of fabric, e.g. whether the fabric will be used for skirts or for window coverings. A fabric drape may be good for window covering, but the similar drape may not be acceptable for skirts. So, simpler attributes signified by polar words, like flexible–stiff, which are related to fabric drape characteristics, need to be evaluated.

2.4.2

Aesthetic concepts of clothing

Clothing aesthetics can be divided into different aesthetic concepts. Figure 2.2 shows the interrelationships among physical parameters, psychological attributes, subjective evaluation and aesthetic comfort of clothing.

2.2 Components of clothing aesthetics.

Following are the guidelines for setting aesthetic concepts related to psychological clothing comfort:

● The concept must be related to at least one of three main physiological sensations, i.e. visual sensation, tactile sensation, or kinesthetic sensation.

● The concept can be a combination of sub-concepts, expressed by words which are more explicit. For example, ‘resilience’ is less explicit than its component sub-concepts ‘compressional resilience’ and ‘liveliness’. Similarly, the term cloth cover cannot communicate the aesthetic concept completely, so its sub-concepts ‘top cover’ and ‘bottom cover’ are used.

● The concepts may be made technically explicit by physical measurements. These measurements attempt to quantify objectively to replace the sense data.

● Aesthetic, concepts or sub-concepts can always be evaluated

subjectively. Subjective evaluation scales are represented by common words (quality words) which express the psychological value of the sense data associated with the concept.

The most commonly used concepts related to clothing aesthetic attributes are clothing cover, drape, body, style, surface texture and resilience [34].

Cover – The cover can be sub-divided into ‘top cover’ and ‘bottom cover’. The ‘top cover’ is the apparent continuity of the surface of fabric, i.e. degree of obscurity of the fabric weave pattern due to surface fuzziness. On the other hand the ‘bottom cover’ is the degree of obscurity of the fabric weave pattern due to fabric sub-layer. The cover can be expressed by dense– open, fuzzy–clean, smooth–rough, full–lean, etc. The fabric cover is objectively measured by streak meter, light transmission, surface contact area, air permeability, etc.

Drape – The fabric drape is generally sub-divided into

‘liveliness’ and ‘fit’. The term drape means the form a fabric will assume due to its own weight when hung freely. The aesthetic perception of fabric drape depends on the behaviour of fabric under static and dynamic states. The fabric drape is expressed clinging–flowing, dead–lively, limp–crisp, sleazy– full, etc. Drape of fabric mainly depends on the bending and the shear characteristics and can be subjectively evaluated by measuring bending rigidity (cantilever or loop method), drape coefficient by drape meter.

Body – The body of a fabric means the overall substance

between the edges of fabric, i.e. the perception of the total substance of fabric during use. The body of fabric is expressed by light–heavy, lofty–thin, bulky– sleazy, full–lean, etc. The fabric body is subjectively evaluated by measuring mass per unit area, thickness, porosity, density, etc.

Style – Style is basically a visual aesthetic perception and

can be perceived through colour, pattern and type of clothing. Clothing style is evolved from the combined perceptions of the textile arts and technology. The style of fabric is subjectively evaluated by measuring the colour value, depth of shade, weave structure, yarn structure, clothing pattern, fit of garment, etc.

Surface texture – The surface texture of fabric means the tactility,

surface roughness and pattern of fabric. This is basically tactile and visual perceptions of fabrics. It is generally expressed by the terms smooth–rough, dry–clammy, grainy–plain, slippery–sticky, slick– greasy, fuzzy or hairy–clean, soft–hard, pricky–soft, warm–cool, dull–lustrous, etc. Subjectively the surface texture can be evaluated by measuring surface roughness of fabric, fabric–fabric or fabric– other surface friction both static and dynamic conditions, optical reflectance of fabric surface, contact point or contact area at the fabric surface, surface fuzziness, etc.

Resilience – It is the ability of a fabric to return to its previous

position after deformation force is released. Generally resilience can be of different type, i.e. resilience from wrinkle or crease, compressional resilience, extensional resilience, liveliness, etc. The perception of wrinkle or crease resilience is the ability of fabric to recover from wrinkle or crease. Similarly, compressional resilience and extensional resilience are the perceptions of the resistance to and recovery from transverse compression and planer extension of the fabric respectively. The liveliness is the perception of the rate of recovery from small deformations. The resilience is generally expressed in terms of bounce–limp, lively–rubbery, lofty– mushy, snappy–stiff, nervous–dead, etc. The subjective evaluation of resilience characteristics of fabric is done by measuring compressional, tensile or bending characteristics of fabrics (e.g. Kawabata evaluation system), vibration damping, crease recovery angle, etc.