Dyestuff

September 19, 2010

I have recently dyed more aerocotton for slotting using Procion MX reactive dye, the previous stocks from my initial experimentation with dye recipes having now run low.  The pipette filler I mentioned in the original dye post has been of great benefit for measuring out the very small and precise quantities of stock solution required for accuracy in the dye recipes.  There are many on the market with huge variation in sophistication and price, but the simple one I’ve been using seems fine.  The wheel mechanism allows very accurate measurement and it is easy and quick to empty.  Although we ordered our filler from Fisher Scientific you can see an image at the following link: http://www.interlab.com.tr/product.asp?cat=0&grup=19

I’ve also experimented with an easier way to dissolve the Glaubers salt (sodium sulfate) in the dye bath.  As it is anhydrous it has a tendency to clump together when added too rapidly to the solution and the resulting rock like particles are very difficult to dissolve.  It is essential to have the salt fully dissolved to prevent the resulting dyed fabric from being uneven, or unlevel, in colour.  Previously I have gradually scattered the salt over the surface in small quantities, vigorously agitating the bath throughout.  This time I tried to pre-dissolve the  salt in a moderate amount of cold water from the total quantity of water used in the dyeing process.  Using water from the overall quantity required is important as the success of the dyeing is regulated by the amount of water to weight of textile ratio and adding additional water would alter the end colour.  However, it was not possible to dissolve the quantity of salt necessary without using a larger quantity of water than the 50mls I took out of the dye bath, and any more would prevent the first stage of the dye process from effectively taking place, that is the wetting out of the textile in the dissolved dye.  Heating the solution is probably the answer – I’ll try this and let you know if this has any effect, good or bad!

Victoria

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Daubeny Project: Light Relief

November 19, 2009

The last few weeks has seen me concentrating on the big questions of light and consolidation.

The Daubeny Library both benefits and suffers from being in its original laboratory setting. The context is wonderful and really adds to the uniqueness of the collection, but the light exposure it suffers from several 3 metre+ high windows which face the book presses is less great. I have been logging light levels over a number of months, as well as setting up a long term light test using samples of the dyed textile used for slotting. Light levels have become somewhat of an obsession due to the work I did on the reactive dyes, as traditionally, and somewhat unfairly, they have always had a reputation of being less light fast than direct dyes. At Daubeny, the UV light levels are encouraging but the visible light levels are slightly too high. It is a difficult space to regulate in light terms as it is used both as a library and a lecture room. Consequently I have been encouraging users to lower the blinds in the room after use, but this has had a variable degree of success. However, any lowering of light levels is a big improvement on the relatively uncontrolled exposure the collection has experienced up until the recent refurbishment of the laboratory.

Consolidation in progress. Image reproduced with the kind permission of the President and Fellows of Magdalen College, Oxford.

The chemically degraded nature of the majority of the leather covering the Daubeny books has also been a challenge. Early tests with the traditional consolidant mixture of klucel g in IMS showed considerable and unacceptable darkening of the leather, and a coarsening of the leather surface. Having done some research into the water content of common solvents, I settled on isopropanol as the solvent of choice. Unlike IMS, with a water content of up to 1%, isopropanol has a water content of less than 1%, and as such seemed a better bet not to darken the leather. I made a 2% solution in isopropanol by gradually adding the solvent to the klucel g, stirring all the time, and leaving it to fully dissolve overnight. This resulted in a very smooth, gelatinous liquid which when applied with a brush caused neither darkening nor streaks across the leather surface.

Victoria (Stevens)

The experiments on the dyeing of spine materials for the Daubeny slotting programme has taken up my time and almost all my thought since my last post on this project.  This is due to it being uncharted waters for me and the criteria being fairly demanding.  I needed a process that was simple and could be achieved in a normal studio setting with the equipment available, and which provided a strong depth of shade using a dye recipe that was easy to accurately replicate.  As the Daubeny books are stored on open shelving good light fastness was also important.  Finally, I did not want a dye which altered the texture or handling properties of the aerocotton chosen for the new spine material.

This search for the holy grail of toning and dyestuffs was quickly narrowed down to 2 dye systems: direct and reactive dyes.  Direct dyes, specifically the Ciba-Geigy direct dye Solophenyl, are used extensively by textile conservators.  They have excellent reproducibility and light fastness but their relatively low wet fastness is an issue.  They also require heat and pH monitoring during the dye cycle leading to a reasonably elaborate procedure.

Reactive dyes, such as Procion MX and Cibaron, or its new incarnation Novacron, are highly solvent resistant due to the strong covalent bond they form between the dye and the fibre.  The dye cycle does not necessarily require heat as the dye is extremely reactive under normal ambient conditions.  This category of dyes have fair to very good light fastness, with the reds being the poorest.  However, this is so with all dyes types.  On the negative side, the highly reactive nature of the dyes can make them difficult to reproduce accurately and can cause unevenness in colour, or unlevellness, across the textile.

Having worked with collections stored in historic buildings I was all too aware of the water based events that can occur involving library and archive materials.  Also, having attended a course on dyeing, arranged by the Textile Group of Icon at the much mourned Textile Conservation Centre (TCC), and witnessed first hand the relatively complicated procedure involved in using direct dyes, I knew reactive dyes were the way forward.

My early results with Procion MX dyes have been very encouraging.  I have benefited from the advice and expertise of Stuart Smethurst at Kemtex, a UK distributor of these dyes, my colleagues at the Oxford Conservation Consortium and the Bodleian, and the mass of literature available on the subject.  I have listed supplier’s information and a brief sample of essential reading for anyone embarking on a reactive dyeing programme below.  These sources also detail recommended dye colours and the dye cycle very clearly, so I will not repeat it here.  However, the problems I had with levellness and reproduction of an exact shade may be avoided by taking care in the following areas:

1. Wetting out: it is important that the fabric is thoroughly wetted before making contact with the dye bath to ensure even uptake into the fibre.

2. The thorough mixing of the salt in the dye solution is also crucial.  The sodium sulphate used is very reluctant to dissolve, and the course information from the TCC recommends making a strong solution of the salt and adding that the dye bath, rather than trying to dissolve it in the bath itself.

3. Agitation: you can not rock the dye bath to much!

4. Rinsing and drying: the smallest amount of residual dye can cause unlevellness, so thorough rinsing in hot water to include a brisk boil wash for around 5 minutes is also important to achieve even dyeing.

With regard to light fastness, the 3 colours I am using have fairly good to very good light fastness.  I have set up light tests on my samples and will report in due course.  Finally, with regards to the inconsistencies in colour reproduction, I am looking into more accurate methods of measuring.  The quantities of dye in solution are so small that even minor discrepancies may cause differences in colour when a recipe is repeated.  A more accurate pipette has been ordered so hopefully this will result in more accurate colour reproduction from the ratios of the stock colours than I have so far been able to produce.  I’ll let you know how I get on.

Toning cloth for boardslotting using Procion MX dyes. Reproduced with the kind permission of the President and Fellows of Magdalen College, Oxford.

Sources of information and suppliers:

Ruth Norton, Dyeing Cellulose-fibre Paper with Fibre Reactive Dyes, The Paper Conservator, Vol 26 2002

Edward Simpson, Dyeing Aerolinen and Aerocotton with Reactive Dyes, Paper Conservation News 71, September 1994

Dyeing Techniques Manual, Textile Conservation Centre, 2008

Timar-Balazsy and Eastrop, Chemical Principles of Textile Conservation, Butterworth Heinemann, 1998

Lerber, Karin von, Cibaron F (reactive dyes) versus Solophenyl (direct dye) for Support Fabrics in Textile Conservation, Newsletter, ICOM Committee for Conservation, 1/96, 3-5

Stuart Smethurst, Kemtex Educational Supplies, Chorley Business and Technology Centre, Euxton Lane Chorley, Lancs, UK, PR7  6TE.  www.kemtex.co.uk, 01257 230220.  Suppliers of dyes and auxiliary chemicals.

Victoria Stevens