The best part of dyeing with cabbage is watching the color change in the dye cups as you adjust the pH. Like the indicator in litmus paper, cabbage gradually changes color from red to blue as the pH increases. This makes it quite a versatile dye. It’s not very stable, but for as long as the color lasts (a few months if you keep it out of the sun), it gives you clean pinks and purples that are otherwise hard to get from natural dyes.
To make a cabbage dye, chop up a head of red cabbage into 1/2″ pieces. Put them into a pot, and fill with water until the cabbage is very nearly covered. Bring the water to a gentle simmer, then turn the heat low. Keep the cabbage warm for half an hour, then pour the water into your dye containers. I like to separate it into three or four containers and adjust them to get different colors. The dye liquid will start out purple. To turn it pink, add an acid, such as cream of tartar or vinegar. To turn it blue, as a base, such as baking soda. Play around with amounts – you can get anywhere from a dusty blue to turquoise to a pale green on linen.
This is also a great way to dye Easter eggs. Cabbage produces the perfect range of pastel colors for the purpose.
Prima came by near the end of these experiments and we dyed a set of old linen napkins, mordanted in aluminum acetate.