I usually print botanical colours by making a cornstarch thickener on paper, and an indulca thickener on fabric. Cornflour is a safer and a more readily available ingredient that indulca. I want to test how well cornflour botanical pastes will print onto fabric.
I simmered the outer leaves of red cabbage for 30 minutes, and left to cool in the dye liquor. Next I strained the mixture through muslin, and then thickened it with cornstarch; approximately 8 g for every 100 g liquid.
I used common kitchen ingredients as modifiers; lemon juice for an acid, and baking powder for an alkali.
I steamed the prints to fix them, using an adapted burco-boiler. Steaming at home can also be done using a large pan of water.
To allow for comparisons, I screen-printed the three different red-cabbage colours onto a range of pre-mordanted fabric, and onto paper. Cotton and silk with soya mordant (kitchen safe), silk and wool with alum mordant (use with care), and leather with iron-water (use with care).
When I contrast these prints with previous research, I can see that the colour yield of indulca based thickener onto fabrics is better than the colour yield of cornflour.
In conclusion I continue to prefer cornflour on paper, and indulca on fabric.
Gather materials that are in your locality. Try to use bio-waste and left over kitchen ingredients, or items that are foraged sustainably. Some of my favourite natural dye ingredients are; onion skins, red cabbage offcuts, turmeric peelings, carrot tops, buddleia, nettles, coffee grinds, and avocado pips.
Soak dried or tough materials overnight. Grind roots and berries. Chop plants into small pieces.
Simmer the prepared materials gently in a stainless steel container with a small amount of water for about half an hour. Leave dye material to cool down. Squeeze through a plastic sieve and/or using a clean tea towel or muslin.Collect the dye liquor. The used plant material can be put onto a compost heap.
The dye liquor can be thickened with common household starch. I like to use cornflour; 8g flour to 100ml dye liquor.
Easter 2017; a collection of dye-plant seeds introduced the wild into Chelsea printroom. The seeds were chosen for a diverse range of colours; Weld (yellow), Woad (blue), Coreopsis (orange), Chamomile (yellow) and Hollyhocks (purple-black). We already had a 2-year old Madder plant whose roots would soon be ready to yield red. The seeds germinated into a straggly array of plants, which rapidly needed more space and light. The fortunate plants were potted into recycled dye buckets, and taken outside. The remainder stayed on the printroom windowsill; reminding students of the provenance of natural dyestuffs.
Tiny quantities of Coreopsis and Chamomile flowers were ready to harvest in July. Majority of the silk was pre-mordanted with Alum.
Foraging, and concocting; with help of expert tutor Penny Walsh, I learnt to use mordants and natural dyes to produce an array of colours. I was astonished at the depth and vibrancy of the colours achieved.