Method o f application for textile conservation

Another important factor in the use of inhibitors in textile conservation is the method of

application. As these materials are expected to be used in a conservation laboratory and on

objects of historic value, several rules apply. To be acceptable for textile conservation

purposes, an inhibitor must:

s be soluble in acceptable solvents for textile conservation, as used in other procedures

like wet or dry cleaning, whilst also not affecting the fibres or dyes. Therefore high

temperatures are not permissible. At the same time, the inhibitors must not interact

with the solvent and must remain unchanged, in order to maintain their stabilizing

characteristics.

s When in solution the pH must also be considered, as acidic solutions will cause

irreversible damage to fibres (Landi 1985, Timar-Balasky and Eastop 1998).

s When in solution the selected methods of application must be delicate to the fragile

textile but also suitable for the essential distribution of the inhibitor in the fibres so as

to be effective. The inhibitor solution must uniformly absorbed by the textile without

causing spots, marks or other visual imperfections.

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S It must not be toxic or dangerous to human health because it will be used in a

conservation laboratory in everyday context, and its commercial form should be handy

and usable.

S It must be easily removable from the textile, using simple, non-destructive, cleaning

techniques. This is because any material added to historic or archaeological objects

may interfere with future analytical work, or a new and better treatment may be

discovered and need to be applied.

5.3 R eversibility o f additives

Based on the last mentioned requirement, the issue of reversibility of additives must be

discussed briefly at this point.

The decision to add new material to historic or archaeological objects has a long and

controversial history. Ideally, in order for a material to be chosen for use during a conservation

treatment it should not cause any changes to the object during its complete cycle of

application, ageing and removal (Horie 1987, 6). Conservators for many years during their

education but also during their professional life know that reversibility is the basic ethical goal

for every treatment (Charteris 1999, 141, Barclay 1999, 157). However, the meaning of the term

“reversible” is questionable in applied conservation and one should give more attention to the

context of this word when making decisions in conservation practice (Oddy 1999,1).

By the term reversibility conservators refer to the potential of removing any material or

reverse the effect introduced to an object by a conservation treatment. This should be the

case both at the time of the application and more importantly after aging. Ideally a conservator

An Evaluation of Photodegradation Inhibitors m the C onservation o f N aturally Dyed H istoric Silks

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treatment occurred, any time she/he wants or she/he is asked to, without causing further

damage to the object (Smith 1999,99). In fact the whole idea is much more complicated than this, because it is clearly proved by chemical thermodynamics that reversibility does not exist

in nature and will never do (Paiazzi 1999,175, Seely 1999,162).

The basic problems of reversibility in conservation context are the impossibility of its

realization and the austerity of the term which allows no qualification (Barclay 1999 ,157).

Although many conservators in the past have tried to reverse previous conservation

treatments, they have never succeeded to ensure complete removal. Therefore, frequently, in

conservation reports and papers it is mentioned that a material or a treatment is “not

reversible” or “very reversible” or even “almost reversible” trying to explain the amount of their

success which is of course not complete. From the above it can be understood that, as far as

the addition of new materials as conservation treatments concerns, the question of their

removal is of primary importance. Removal is an action that can have several degrees and

can be measured even with scientific methods (Barclay 1999, 159). Therefore if a

photodegradation inhibitor is selected to be used to an historic textile, its removability should

be checked more preferably after ageing. The degree of removal of the additive, the method

needed to do so, and the prospective damage caused to the object by this action are the

points to be evaluated.

All conservation treatments may cause damage, and if new materials are added they

will surely leave residues, even small, and this cannot be avoided or completely removed

(Smith 1 99 9,10 0 ). So the fundamental issue is the understanding of the ageing characteristics

of the materials used (Paveika 1999,105) and their behaviour in the future in accordance to the object it is applied to. Having in mind that an inhibitor would never be totally removed from a

An Evaluation o f Photodegradation I n h ib i to r s in th e C onservation o f N aturally Dyed Histono S ilks

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textile, but still it is judged beneficial to the improvement of its light stability, it is important to

predict its performance after ageing and possible negative effects on the textile components.

According to this value, the whole idea of reversible treatments over the years helped

conservators to minimize unserviceable treatments, especially in restoration work, and make

them more responsible in choosing the correct materials and methods of application. But also,

the idea of reversibility made some people critical to any interventive treatment and any new

material introduced (Paiazzi 1999,177). In this way no conservator wants to put him/herself to

criticism to decide for a new treatment and this attitude is capable of stopping further

evaluation of a promising new treatment (Smith 1 9 9 9 ,101). Of course this does not mean that it

is acceptable to treat any object with any material. On the contrary, all interventive treatments

should be considered, thoroughly tested and justified before chosen to be applied to an object,

but it has to be understood that most treatments are not and cannot ever be reversible (Oddy

1999, 3).

As far as photodegradation inhibitors tested in this research are concerned, under

conservation requirements, consideration of their removability from treated textiles is

essential, and must be considered as one of the important factors relating to their suitability for

museum textiles.