Surface patterning and dyeing approaches

Textile Designer Jenny Addrison (2009), explored Laser surface modification of woven structures for dyeing at Loughborough University (LU). This study made use of different departments at LU including the School of Art, Department of Chemistry and Department of Materials. Therefore, this was probably one of the first attempts to approach textile design in a scientific way in terms of experimental rigour regarding methods, procedures and results, underpinned by a creative perspective, akin to this interdisciplinary laser-dye research.

Bartlett’s (2006) study, Laser and textiles: an exploration into laser dye-fibre interaction and the process of technology transfer also linked across departments at LU – the Art School and Wolfson School of Mechanical and Manufacturing Engineering as well as collaboration within the fashion industry. This work combined laser technology and dyeing to some extent however, investigation was limited in terms of experimental and creative exploration of the laser-dye process and the research results.

Bartlett (2006) was concerned with how experimental results of textile surface explorations with the laser might be applied in commercial garment production. Therefore, collaboration with haute couture fashion designers was embedded into the research framework. A CO2 laser was used to char the surface of different natural fabrics including cotton/denim via a laser etching method similar to Stoyel (1996; 1999; Miraftab and Horrocks 2007), Lockman and Clayson (1996) and Ondogan et al. (2005). The aim of this approach was to generate a range of damage levels in order to aid the creation of images with a raster halftone CAD method.

The results of such investigation was demonstrated by a range of laser etched fabrics and denim garments. This work also presented a method for staining (rather than dyeing) fabrics.

Some experiments were carried out with polyamide fabrics using Nd:YAG and Ruby laser systems and disperse dyes via hand and manual procedures. To observe dye uptake, fabrics were first placed in a solution and laser treated whilst the sample was wet. In doing so, a few test samples of the results demonstrate the feasibility of the process. However, these initial results were not explored further from a scientific, technical and creative understanding of the process and so did not include a sizable range of laser processing parameters, microscopy or design development demonstrating artistic input for textiles or potential application within a fashion and garment production context. It was assumed uptake capability was based on dye absorption of a particular dye/shade in response to an energy dependant function such as heating, caused by laser beam interaction (Bartlett 2006, p.205), also influenced by time and temperature, suggesting results could be improved by applying a longer pulse of laser energy (ibid., p.221). An attempt to analyse fabrics is presented in the study with tear and tensile strength tests undertaken.

Prior to Bartlett’s study (2006), laser-dyeing methods were already established. Although some work was done by Bartlett, the conclusions of her pulsed laser work were not sustained with any detailed experimental work. No attempt was made to quantify or systematically investigate any of the basic control parameters necessary to optimise the laser, nor describe an image density method in terms of shade depth against energy density. Design development with imagery was therefore limited. No micrography documented means there is no evidence that seeks to investigate the mechanism for enhanced dye uptake or analyse dye performance. Similarly, no comprehensive analysis of the results has been provided regarding laser treated and performance tested fabrics. For example, washability and durability aspects have not been discussed. As such, the results are non-transferrable/non-repeatable methods, procedures and results, as well as issues with the accuracy of outcomes. Instead, an initial set of findings have been reported within a limited experimental scope of the project. Earlier studies however, such as Lau et al. (1997) and Yip et al. (2002) for example, (further discussed in section 2.5 of this chapter), evidences scientific and technical investigation regarding combined laser/dye methods. These studies report quantitative analysis of the results and are therefore reliable in a way that is not evident in Bartlett’s work.

Addrison’s investigation combined laser and dyeing methods in order to explore colour and pattern with differential dye uptake techniques. Cotton, polyester and poly/cotton commercially available woven fabrics and dyes (rather than industry standard dyes) were employed. Using a CO2 laser bed system to etch fabrics, an experimental approach was pursued in order to understand interactions between the laser beam, textile fibres and dyeing. As with traditional devoré methods (previously discussed in this chapter), also explored by Stoyel (1996), dual fibre poly/cotton fabrics enabled multi shade effects demonstrated by bold geometric designs achieved with a CAD approach (Figure 13).

Commenting on the results Addrison (2009, p.7) remarked, ‘Devoré only allows for one additional colour yet by laser etching, numerous shades can be produced’. Quantitative data was obtained through microscopy, spectroscopy reflectance testing and dye absorption measurements. This information steered creative development and facilitated an understanding of the opportunities and limitations of combined laser/textile/dye processes for textile design within the scope of the project. Results of the study provided the platform for the start of this research surrounding the digital laser-dye process. As such, this work aimed to explore laser technology as a creative graphic patterning tool via digital coloration methods for polyester fabrics and apparel, relevant to industry.

Figure 13: Laser textile patterns – ‘cross-dyed’ poly/cotton (Addrison 2009)

The aforementioned studies (Bartlett 2006 and Addrison 2009) demonstrate the significance of laser processing as a creative tool for textile design.

Laser-dyeing discussed in this thesis focused on fibre modification fused with dyeing in order to initiate new graphics within a textile design context. This work demonstrates a thorough understanding of a method for generating a range of tones with one shade using a digital patterning approach. A scientific and technical experimental approach relevant to industry standards enabled rigor and the communication of techniques and procedures involved. Other studies such as Bartlett (2006) for example, do not do this in terms of the creative opportunities of a laser/dye approach.

2.5 Laser modified synthetic textiles: fibre, laser and dye