Monday, June 2, 2014

Dye Plant -- Colors of Red Cabbage

Many household products, such as coffee, tea and turmeric, are effective dyes. I have gotten good colors from spinach (link), but don't find much dye in iceberg lettuce or yellow cabbage. However, red cabbage, Brassica oleracea, turns the water a lovely shade and can be fun to dye with.

Unlike spinach, which gives colors from olive to yellow depending on the mordant, red cabbage is pH sensitive. That is the key to the dye project described below.

I started with one red cabbage.

Dyestuff: 1 red cabbage, Brassica oleracea
Dyestuff: 1 red cabbage, Brassica oleracea

I purchased distilled water. Distilled water has no trace of anything in it and is of neutral pH. In fact, the pH of distilled water is defined as the middle of the pH scale, 7.0. 

Chop the dyestuff for more surface area
Chop the dyestuff for more surface area
Put chopped dyestuff into a bag.
Put chopped dyestuff into a bag.
Heat in distilled water, 1 hour
Heat in distilled water, 1 hour, not quite boiling
Meanwhile I premordanted bits of silk cloth and wool yarn by heating them in water to which alum (aluminum ammonium sulfate, used in pickling, bought at a pharmacy) had been added. 7-10% alum by dry weight is standard, but I estimated the amount.

Premordant fibers to be dyed in water with up to 10% alum
Premordant fibers to be dyed: in water with up to 10% alum
See the water change color where the cabbage is heating!
Dye bath with red cabbage.
Dye bath with red cabbage.

I divided the dye into 3 parts. Into one I put 2 pieces of silk and one skein of yarn and heated (without boiling) for an hour. This is the color of the dye bath at neutral pH.

Dyeing in red cabbage juice, neutral pH (pH 7)
Dyeing in red cabbage juice, neutral pH (pH 7)
I made the other two parts of the dye alkaline and acidic, respectively. To the first I added a generous teaspoon of baking soda (sodium bicarbonate) making the pH alkaline. To the second I added a tablespoon of vinegar (acetic acid) making the dye bath acidic. The color change was immediate.

Red cabbage dye with baking soda added (alkaline pH.)
Red cabbage dye with baking soda added (alkaline pH.)
Red cabbage dye with vinegar added (acid pH.)
Red cabbage dye with vinegar added (acid pH.)
I heated each for 1 hour, without boiling.

And here is the result. The silk worked well, the wool yarn not as well.  From left to right: alkaline, neutral and acid on thirds of a single batch of red cabbage juice. In my photo they are wet, dry the color is not as intense.

dyed with red cabbage: alkaline, neutral and acid conditions
dyed with red cabbage: alkaline, neutral and acid conditions
I don't know what happened with the wool. Wool yarns vary a lot. Perhaps I didn't mordant well, perhaps the wool had been treated with something I didn't get washed off, or perhaps cabbage never adds much color to wool at neutral pH. More experiments needed.

I also don't know what will happen if I add 2 teaspoons of baking soda or 2 tablespoons of vinegar.

I discovered this by accident, expecting a nice pink and getting a bluegreen at a demonstration--apparently different pHs in my tap water and at the University of Northern Colorado. I think the method here should work for everyone because it begins with distilled water. If you use tap water, you'll find out something about your water's pH.

Before you plan a summer wardrobe dyed with red cabbage, I should point out that not one of my 15 natural dyeing books works with red cabbage. Therefore, I think the colors may fade or, encountering something of a different pH, change color. Mine have their color after a month indoors, however.

As always, natural dyeing is an adventure and a delight!


Comments and corrections welcome.

Kathy Keeler

I put a link to an update in the comments, but it isn't "live": here's the link http://khkeeler.blogspot.com/2015/09/dye-plants-colors-of-red-cabbage-update.html






11 comments:

  1. I found that my alpaca fibers were wash fast and light fast when I premordanted them with myrobalan (which makes a butter yellow). I'm thinking that maybe the alum blocks the absorption of red cabbage dye on wool since the dye is water soluable and the alum salts are coating the fibers. Possibly mordanting AFTER I dye may yield better results?

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  2. Lovely post with clear instructions and great pictures. Can I ask how the silk is one year on? Has the colour faded or changed at all?

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  3. I couldn't figure how to upload a photo to answer Saffi's question, so I wrote an update post http://khkeeler.blogspot.com/2015/09/dye-plants-colors-of-red-cabbage-update.html (this blog, Sept. 17, 2015)

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  4. Well I am just so grateful for this post! My first go with red cabbage has been a surprise. I used my raw, unfiltered well water, which I know has iron in it, to extract dye from the cabbage. The water is a deep indigo. Does that mean my water is alkaline? How wonderful if so! Also, I am using 100% cotton. Maybe it was pretreated. I'm not sure. I didn't use a mordant for my initial attempts. I'm going to try using alum now. Or maybe cream of tartar.

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    1. I have some Rambouillet already spun and for the first time, steamed a red cabbage. I also have unfiltered well water - it was a beautiful marine blue and I know I have iron in it. I just may experiment with it and see what I come up with. LOVE that blue. It's almost sapphire.

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  5. Glad you had such fun! The iron in your water probably acted as a mordant. Most mordants are metal ions that bind to the cloth. So you have four differences from my experience: water pH, iron in the water, no alum and cotton fibers. Any or all of them could have determined the color. Iron as a mordant saddens (technical term) the color, making it less bright and generally darker. You might learn a lot from using distilled water and doing everything else the same. Did the cotton turn deep indigo?

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  6. The link to a year later didn't work. 😓 Perhaps, there's a different link?

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  7. Goatberry: I added the link to the update on the bottom of the original post.

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  8. Wow, great post. Thanks! Do you know how colorfast or lightfast the cabbage dyes are? It looks like you posted in 2014. I'm curious to know if the color has held up!

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  9. Follow-up post. They aren't color-fast. See http://khkeeler.blogspot.com/2015/09/dye-plants-colors-of-red-cabbage-update.html

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  10. Very cool! Thank you for sharing.

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