devore; print workshop notes.

      silk viscose velvet - silk viscose satin

DEVORE

There are two main recognised methods of devore. They both rely on the basic construction of the cloth that is treated.

One mix of chemicals attacks protein fibres and the other destroys cellulose.

This technique is applied to mixed fibre cloths where one or more of the fibre types are destroyed, leaving an embossed effect with both solid and translucent areas.

Common devore fabrics available on the high street are silk viscose velvet and silk viscose satin which have been popular over the last few years.

There are many other fabrics specially designed for this technique which mostly rely on the cellulose fibres being destroyed.

However many exciting results can be produced on fabrics not designed for devore purposes and it is worth experimenting with unusual fabric combinations.

For successful effects it is important that there are different fibres present in both the warp and weft of the fabric or the cloth might fall apart.

If a cloth with a single fibre is used and printed with a careful selection of design, whole shapes can be burned away, producing a delicate frame work.

Where a devore resistant fibre is present in only the warp or weft, a floating thread technique can be created.

Once the basic principles of devore are understood, more adventurous work can be done with fabrics that have two or more devore resistant fibres. Multi layered effects can be produced by layering different fabrics together - cotton and wool, cotton and polyester or silk and viscose. The fabrics are then stitched or bonded together in places so it is possible to burn away areas of the top cloth, revealing the bottom cloth, thus creating a multiple cloth.

Interesting colour effects can be achieved by dyeing one or more fibre in a multi fibre cloth e.g. a polyester cotton coloured with a disperse dye will have a chalky look because the cotton has not taken up the dye. When the cotton is burnt out the full shade of the polyester will be revealed. This technique can be taken a stage further by cross dyeing the two fibres in contrasting dyes and colours.

Many complex colour patterns can be created by using various reactive and resist processes alongside the devore technique.

Many factors have to be considered when producing successful devore; the strength and amount of paste applied to the surface of the fabric ; how the paste is applied, screen printing is by far the best process as you can control the amount needed. Hand painting and block printing techniques can leave inconsistent results during the burn out stage ; the length of time the paste is heated, too long and too hot will damage the other fibres in the cloth, producing holes.


DEVORE FOR CELLULOSE FIBRES


This technique burns away all cellulose fibres - cotton, viscose and linen, but will not damage silk, wool and synthetic fibres.

The degradation of cellulose fibres are achieved by the use of an acid such as aluminium sulphate or sodium hydrogen sulphate. With the application of heat the paste forms an acid that carbonises the cellulose printed areas.


70gm solvitose powder

50gm aluminium sulphate

20gm tartaric acid

2tsp glycerol

400ml water

WARNING, THIS CREATES SULPHURIC ACID DURING PROCESSING

Dissolve the aluminium sulphate and tartaric acid in a little hot water. Mix into solvitose and add glycerine.

Put 10gm solvitose powder and 400ml water into liquidiser and whiz.

Add solvitose, aluminium sulphate mixture to the liquidiser and whiz.

Mix until a smooth syrupy mixture is achieved, leave the devore paste to stand for 30 minutes.


Screen print the paste onto the fabric making sure it penetrates the fabric, usually six or eight pulls for a medium fabric should be enough. When using silk viscose velvet always print on the reverse of the cloth rather than on top of the pile.

The fabric is dried before being heat treated. If the print is not completely dry during this process it will not get hot enough to carbonise and the results will be poor.

The fabric is then baked at 170C for 5 minutes or heat pressed at 170C for anything from 30 seconds to 2 minutes or ironed until the cellulose has carbonised, turning a brown - black colour. Experimentation is required at this stage.

The carbonised fibres are removed by gently rubbing the fabric in an open area - preferably outside. IT IS IMPORTANT AT THIS STAGE TO WEAR A MASK, GLOVES AND GOGGLES AS THE FIBRES AND CHEMICAL DUST ARE IRRITANTS.

Do not rub the fabric too hard as the fabric is brittle and holes are easily made.

The fabric can then be washed in warm soapy water until the burnt out areas are removed.

If a coloured fabric is wanted the fabric can be dyed before or after the burn out process.

DEVORE FOR PROTEIN FIBRES

This paste destroys protein fibres - silk and wool with a strong alkali, leaving cotton, viscose, linen and synthetics untouched.


400ml water

60gm solvitose powder

50gm sodium hydroxide pellets (caustic soda) dissolved in 100ml water.


WARNING: PLEASE TAKE THE NECESSARY SAFETY PRECAUTIONS WHEN PREPARING THIS RECIPE SINCE IT USES CAUSTIC SODA WHICH IS PARTICULARLY HAZARDOUS. ALWAYS USE EYE PROTECTION, LONG SLEEVES AND MASK. THEY ARE ESSENTIAL AT ALL STAGES OF THIS PROCESS TO AVOID ALKALI BURNS.

Add the granules to the cold water in a chemical resistant container and not the water to the granules. A great deal of heat and fumes are emitted at this stage. When cold add the caustic soda solution to the thickener. Mix into a smooth paste.

Follow the same steps as the cellulose devore recipe, printing,drying, carbonising and washing out. After washing, the alkali in the fabric is then neutralised in a solution of 2ml acetic acid per litre of water.

Another way to carbonise the protein fibres is to steam the print for ten minutes rather than heating it. This will cause the the caustic solution to destroy the protein fibres in the printed areas.

When using larger pieces of fabric, instead of heat pressing or baking, the fabric can be steamed. A stronger solution of caustic soda must be used for this method. Once the fabric is printed and dried it is steamed for 15 minutes until the protein fibres turn a yellow orange colour.

The cloth can be dyed before or after the devore process.