Depth of shade, dye quantities, auxiliaries, stock solutions, & water ratios
Colour Strength is expressed as Depth of Shade. (D.O.S) which is calculated as the amount of dye as a percentage of the weight of fibre (W.O.F). e.g 1gm dye to 100gms fibre = 1% Depth of shade.
The strength of colour does vary considerably on many dyestuffs. To determine the colour value produced by a particular amount of dye per weight of fibre you can use the following guidelines. 0.5%(D.O.S) lighter shades, 1% D.O.S medium shades and 2% to 4% (D.O.S) deep stronger shade.
To make calculations easier to work out we use the metric system.
Calculating Dye Quantities…fibre weight x (%D.O.S) divided by 100
Example 1. 125gms yarn dyed to 2% D.O.S. how much dye required ?
Multiply 125gms x 2 = 250gm divide by 100 = 2.5gms dye.
Example 2. 300gms fibre dyed to 3% D.O.S. how much dye required ?
Multiply 300 gms x 3 = 900 divided by 100 = 9gms dye
Auxiliaries
| Light shades | Medium shades | Strong shades | |
|---|---|---|---|
| Citric Acid | 1%(W.O.F) | 1.5%(W.O.F) | 2% (W.O.F) |
| Glaubers Salts | 2%(W.O.F) | 10%(W.O.F) | 5%(W.O.F) |
| Lyogen NH | 1%(W.O.F) | 1.5%(W.O.F) | 2%(W.O.F) |
Stock Solutions
This can be described as a specific amount of dye powder dissolved in a particular amount of water.
Stock solutions are a great time saver as you can make a batch which you can use many times over until it runs out. It is easier to use the stock solution than to measure small quantities of dye powder every time , and when trying different D.O.S for certain colours you can easily measure the amount of stock solution for that colour. Just make sure you label & record what your solutions contain. You can now measure small quantities easier & accurately.
Most stock solutions will last 3-6 months stored away from sunlight. Some do not last that well and their effectiveness may only be 1-2 weeks.
Calculating a 1%Stock solution
Please note: if you wish to avoid lengthy calculations, use 1% stock solutions.
1% stock solution is the total volume of stock solution required divided by 100.
Calculating 1% stock solution for 1000gm (1kg) fibre. Here, you change the measurement of weight to volume eg 1000gm to 1000mls. You would therefore add 10gms dye (1%) to 1000mls water to make the 1% stock solution.
To mix a 1% stock solution
Example 1. 500mls of stock solution… divide 500 by 100 x 1= 5gms dye.
Example 2 800ml stock solution…divide 800 by 100 x 1 = 8gms dye.
Both examples have a dye strength of 1% depth of shade. (D.O.S)
To calculate the amount of 1% stock solution required per dye lot.
Make stock solution using a 1000ml (1 litre) 1% Stock solution.
- Example 1. (W.O.F) 120gms divided by 1(% D.O.S.)= 120 mls
- Example 2. (W.O.F) 350gms divided by1=350 x 2(% D.O.S) = 700 mls
- Example 3. (W.O.F) 55gms divided by 1= 55 x 3(% D.O.S) = 165 mls
If you wanted to change the formula to another % of stock solution then you would simply follow the same formula .eg 2% stock solution = 20gms dye per 1000 mls water.
Lyogen NH Stock Solutions
Lyogen NH is measured at 1- 2% (W.O.F). 1% light shades , 2% heavy shades.
Eg to 1000mls water add 2% Albegal set =20gms. Shake mixture well every time it is used as with all stock solutions.
Water Ratios
Use a ratio of 20:1 for fibres such as wool and alpaca.
Example: 1kg (1000gms) fibre x 20 = 20litres. If this does not cover the fibre adequately then increase rate to 30:1.
Bulky fibres such as silk require a water ratio between 30:1 & 40:1.
