Today I made more dye experiments with red cabbage. This time I made a dye bath with red cabbage and baking soda. I diluted leftover homemade blue food coloring (made with red cabbage and baking soda) with water. The food coloring turned the water dark blue, almost black.
I put pre-washed white cotton fabric scraps into the red cabbage + baking soda dye solution and let the scraps soak for different amounts of time: between a few seconds and about 5 hours. Then I removed the fabric scraps and let them dry. During drying they become more green.
After drying, I washed them in lukewarm water. But the addition of baking soda makes red cabbage dye not washfast: After washing the fabric scraps are all only light blue. The beautiful teal color is gone!
For another dye sample I mixed red cabbage food coloring with soy milk. I let the fabric soak overnight in the red cabbage-baking soda-soy milk dye bath. Before I washed the fabric it was turquoise like the dye bath, but after washing it’s also just light blue.
Update: Apart from not being washfast, the addition of baking soda to the natural dye solution also make the dye not lightfast. After a few days exposure to light, all red cabbage + baking soda dye samples faded badly. The fabric scrap which I left unwashed turned beautiful green (it was blue before). But the fabric scrap which I washed in lukewarm water faded to grey. The scrap at the bottom was just some minutes in the dye solution (it’s also washed in lukewarm water): it’s bluish grey.
I cut up the washed fabric scrap (in the middle) to test three modifiers: a weak solution of baking soda, baking soda & vinegar and vinegar. Baking soda turned the fabric pinkish grey. Baking soda & vinegar and vinegar, both modifiers helped to preserve a light green color.
So this dye experiment showed that the ph-level is very important when you want to dye cotton fabric blue with red cabbage. If the red cabbage dye solution is too basic it won’t dye a washfast and lightfast blue.
Related: How To Dye Cotton Blue With Red Cabbage (DIY Iron Mordant, Cold Method)
Hi!
I’m currently trying to obtain a deep blue. My test strips until now turned out either green or purple/blue. Do you think there’s a way to maintain the deep blue before it turns green? Thank you so much!
Red cabbage-baking soda-dye is not very light- and wash-fast. If you want to dye cotton fabric blue, rather mordant the fabric with DIY iron liquor and use red cabbage dye (without backing soda). Here‘s my tutorial.