Wednesday, 29 August 2012

Lowering the pH for Acid Dyes

Wensleydale wool dyed with Acid Dyes
Curly Wensleydale wool dyed using Acid dyes
Citric Acid is a weak organic acid used as an acidifier in dyeing.  It will alter the pH level of the dye bath and is an odourless alternative to white vinegar when immersion dyeing protein fibres such as silk and wool with Acid Dyes.

If you are painting or printing with Acid dyes, or using Procion MX dyes as an acid dye, and wish to steam or microwave set the dyes, the fabric should first be pre-soaked in a solution of Citric Acid and allowed to dry before painting.

The term “acid” in Acid dyes refers to the relative pH balance of the dye bath.  The pH is dependant on the concentration of the acid in water, which in turn depends on the actual volume of water.  The level of pH is measured on a scale of 0 to 14 with 0 representing the highest concentration of acid and 14 representative of the most alkaline.

0.5% by weight of Citric Acid (i.e. 5g in 1 litre of dye bath water, or 25g = 1oz in 5 litres = 1 gallon approx) gives a pH of 4.0.  This is in line for Levelling Acid Dyes (the family of acid dyes sold by George Weil) where the recommended pH is around 4.0, and this acidity also works well for the other acid dye families, Milling and pre-Metallized. 

As always this assumes that the water in the dye bath started at pH 7.0, which it may not, so testing with universal litmus paper is strongly recommended to ensure the correct acidity.  This is equally true when using vinegar.   

The post "Chemistry of Textiles and Dyes: pH" on Chemistry Art Blog explains further how the pH effects dyes. 

View the range of Acid dyes on the George Weil website.  

Friday, 24 August 2012

Printing with Dyes and Paints

There are a number of thickening agents and assistants available from the George Weil website.


Silkpaint Resist is a water soluble resist which when applied to fabric, can be used as an outliner to define areas in silk painting or to block out areas to create batik effects. Dye or silk paint colours can be added to the resist to tint it. Diluted with 3 parts water, it can be painted onto fabric to help inhibit the flow of paint. Combining the resist with dye thickens the dye so that it can be used for painting or screen printing. Steam, heat set or fix dyes according to manufacturers’ instructions, machine wash on delicate cycle and iron while damp.


Indalca PA3R is a Guar Gum based thickener, with properties similar to Locust Bean Gum. It can be combined with dyes for painting or screen printing (1 part Indalca PA3R to 10 parts water), and as it has good stability in both strongly acidic and strongly alkaline conditions, it is recommended for use as a thickener for Disperse Dyes when heat transfer printing. Disperse dyes are for colouring synthetics such as nylon, cellulose acetate, vilene, viscose, polyester, synthetic velvets and PVC. They can also be used to colour plastic buttons and fastenings. Their effect is less potent on polyester, due to the molecular structure, allowing only pastel through to medium shades. Polyester fibre contains pores or canals within its structure which, when heated to 100°C, expand to allow particles of the dyes to enter. The expansion of the pores is limited by the heat of the water - industrial dyeing of polyester is carried out at 130°C in pressurised equipment! Full colour can be achieved when heat transfer printing with disperse dyes.


Manutex, or Sodium Alginate, is derived from seaweed and forms a viscous gum when combined with water. Manutex F is used when fine line definition is desired and for overprinting. Add 100g to 1 litre of cold water with 10g of Calgon. Add thickened water to dyes until the desired consistency is achieved. Manutex RS has a lower solid content than Manutex F and is used primarily for prints on thicker fabrics and on silk when fine definition is not required. Use 45g to 1 litre of cold water and add 10g Calgon. Calgon Water Softener helps to eliminate the effects of calcium and magnesium salts in the water which make colours weaker and duller. UREA Urea can be added to printing pastes to increase the solubility, and therefore the brightness and intensity of dyes. As a humectant it retains moisture even when dried, and this boosts the colour yield of the dye during the fixing stage. 

Although these thickeners have been used successfully with many dye products, testing before starting a project is recommended.

Friday, 17 August 2012

DEKA Transparent & DEKA Cristal

George Weil have been selling the range of DEKA paints for many years and they continue to be popular with our customers. 

The DEKA Transparent and DEKA Cristal paints are fully transparent, bright colours which dry to a glossy finish on glass, metal, wood, ceramic, polymer clay, metal foils, acrylic and more.  The difference between the paints are that DEKA Transparent are solvent based and DEKA Cristal are waterbased acrylics.  Both paints air dry hard and can be heat hardened further in an oven.

DEKA Transparent paint has excellent adhesion and can be heat hardened so that it becomes scratch resistant. The colours are intermixable and intensity can be built up with additional applications.  Used sensibly, there should be no safety issues with this durable paint, the solution is flammable and should be used in a well ventilated space, accidental spills cannot be removed and brushes must be clean-up immediately with DEKA Transparent Thinner.   

With its acrylic base, DEKA Cristal is a better option for painting porous surfaces such as wood, plaster, and cardboard.  The paint cleans up easily with soap and water.

The photograph shows some examples of how the paint can be used.

a) A ceramic salt pot painted first with DEKA Outline Paste which was heat hardened in an oven for 30 mins at 120˚C.  Elements within the outline were then painted with DEKA Transparent.
b) A metal fish charm painted with DEKA Transparent.
c) Polymer clay shaped, and then painted with DEKA Transparent before baking for 30 mins at 120˚C.  The finish is very similar to a fire glazed ceramic.
d) Wooden beads painted with glossy DEKA Cristal (red) and DEKA Transparent (dark blue).  The paints were applied over varnish.
e) A plastic elephant cracker gift made to look like a miniature ceramic with DEKA Transparent.
The handle of this wooden spoon has been painted with  DEKA Cristal

Wednesday, 8 August 2012

The Pocket Color Wheel - a guide to mixing colour

The Pocket Color Wheel (yes color - it is made in the U.S.A.) is an essential tool for learning all about colour.  The wheel consists of three cardboard discs which are joined in the centre.  The middle wheel has the 12 main colours positioned equally around the edge while the discs either side have holes cut-out which reveal different colour results as they are turned.

The Pocket Color Wheel - colour mixing guide
The Pocket Color Wheel

This front side (shown in the photograph) covers all the basics such as the three primaries, red, yellow and blue, which cannot be made by mixing other colours, and the secondary colours such as violet which are made by mixing two of the primaries, i.e. red and blue make violet. By turning the front disc, you can find out at a glance how adding white, black, or any of the primaries will have on the original colour.  The photograph shows the position of the front disc turned so that it reveals what will happen if yellow is added to blue-violet, resulting in olive green.

The disc on the reverse side of the wheel explains colour relationships.  Each pure colour is broken down into a tint (the colour plus white), tone (the colour plus grey), and shade (the colour plus black). In the centre of this disc is a diagram which signifies all the colour relationships (such as complementary and triad) which are explained by the glossary of Harmonious Colour terms, helping you to select colour schemes for your projects. 

The Pocket Color Wheel is an indispensable tool for the artist, weaver and interior decorator.

Please visit the website if you would like to order the Pocket Color Wheel (product number EB426) from George Weil.

Wednesday, 1 August 2012

Block Printing with Speedball Speedy-Carve Blocks

The Speedball Speedy-Carve Blocks (previously known as Speedy-Stamps) can be used for creating blocks for printing onto a variety of surfaces.  The blocks are faster, safer and easier to carve than traditional linoleum.

The rubber is so flexible it can be bent around curved objects for printing onto flower pots or jars, and dense enough to use for creating patterns on polymer clay or silver clay. The blocks will not crack, cumble or break.

Speedball Linozip Safety Cutter for cutting blocksThese latex-free rubber blocks are easily carved using the Speedball Linozip Safety Cutter which has a hollow handle for storing the variety of blade shapes that come with it.  The cutter is designed to be pulled towards the body allowing for greater control in carving and ideal for use by beginners.

The photograph shows two cut blocks and our Fact File page explains how a two colour print can be created from the Fleur-de-Lis block.  The right hand block was made by Alison Bate.  Her prints, below, were made using Jacquard Lumiere paint and include (from left to right) a silk scarf, a chiffon scarf, a canvas cotton purse and a handmade card using Lokta printable card blanks and coloured Mulberry paper.  Visit the Block Printing section of the George Weil website to view the products available in this range.