STOKE THE FIRE
The first length
One length of madder, plain alum
ALUM
A dye is soluble on its own and insoluble once a metal holds it to the fibre. Mordanting is a job of its own: dose the pot, get the pH and the heat right, and let the wool fill. Dyeing is another: charge the copper, watch the bath go pale as it gives itself up, and lift before it stops giving. Then wash it, and see what was real.
- MORDANT FIRSTWithout a metal on the fibre the colour only sits there, and the wash takes all of it.
- TOO MUCH DULLS ITExcess mordant cannot be held, and it greys the lake. There is a dose that is right.
- THE BATH RUNS DOWNDye lifts what is in solution, so the second length through the same copper comes out paler than the first.
The buyer holds it to the light.
Nothing moves while you are here.
The clock does not run either. Both baths, the batch and the commission are where you left them.
How a colour is fixed.
- THE ORDER OF WORK
- Alum in the pot, wait for the load to fill, lift, then into the copper with the colour. Skipping the pot is the one mistake that loses everything: the dye has nothing to bind to, sits on the surface, and the rinse takes it.
- THE DOSE
- Every press of a mordant is a scoop. Two is the working dose; three is more metal than the lake can carry, and the excess greys the colour. Read the dose on the pot meter and the load on the length.
- THE pH
- Each dye and each mordant has a window, marked on the meter. Soda ash raises it, vinegar brings it down, and a pot of alum drifts acid on its own. A logwood bath also writes its pH into its own colour.
- THE HEAT
- Stoke to set the fire, then wait: a copper vat takes a couple of minutes to come up. The clock runs only while a bath is over 55 °C, so a cold vat is free thinking time.
- THE CHARGE
- A press of dye is 6 g into 26 L. One press carries about one length. Two presses carry a batch, and four are so strong the colour strikes out on the surface as a flat bloom.
- WASH AND DRY
- The rinse takes the loose dye and a little of the lake. Drying oxidises what is left and deepens it. The swatch shows the colour as it came out and the same colour after the wash.
- KEYS
- SPACE main move · ↑↓ stoke · ←→ dye · Z mordant · 1–3 length · C scoop · V charge · J rinse · K dry · E send · P speed · ESC pause · M mute · H this book.
The model is a real one. Colour is Beer-Lambert absorption through a dyed fleece: each dye has an absorbance spectrum, the mordant blends it toward its own metal-dye lake, and the result is compared with the buyer's standard in OKLab. A length that was not properly mordanted has fewer sites than dye, so the surplus was never fixed and the wash removes it. A length left in a bath that has nothing left in it stops short, and the next length finds it weaker still.