Alum = potassium aluminum sulfate
Cream of tartar = tartaric acid
Animal fibers include wool, silk, angora, cashmere, mohair, llama, alpaca, etc.
Alum is fairly easy to find, as it has a number of common uses: as soil conditioner for acid loving plants, in water treatment, for pickle making.
Cream of tartar is commonly used as a cooking additive: for homemade baking powder, to stabilize egg whites in meringues, in winemaking, even as a natural cleaner.
In natural dyeing alum is used as a mordant. The purpose of a mordant is to fix the color to the fiber. With alum, the cream of tartar assists in the take-up of the alum in animal (protein) fibers.
In researching, I find I have three books on the topic and four different recipes.
Jenny Dean (Wild Color)
- 8% alum per weight of fiber
- 7% cream of tartar per weight of fiber
So, for 1 pound fiber or yarn that comes to
- 1.28 oz alum
- 1.12 oz cream of tartar
Rita J. Adrosko (Natural Dyes and Home Dyeing)
- 1 pound wool
- 4 oz. alum
- 1 oz. cream of tartar
Rita Buchanan (A Weaver's Garden)
Quick recipe
- 1 pound wool
- 4 tbsp alum
- 4 tsp cream of tartar
Technical recipe
- 14% alum per weight of fiber
- 4% cream of tartar per weight of fiber
For one pound of wool that comes to:
- 2.24 oz alum
- 0.64 oz cream of tartar
Quite a bit of variation! But which is correct? Which is best?
Since I lost my notes from my previous natural dyeing experiments, I opted for the easiest recipe - Rita's quick recipe so I wouldn't have to figure out percentages. For my records, here's what I did
Procedure
- Thoroughly wet the fiber. Soak in clean cool water for an hour or two
- Measure chemicals into a glass jar and mix with boiling water until dissolved.
- Add to 4 gallons of cold water; mix well.
- Add wet fiber
- Heat slowly to a simmer and simmer one hour.
- Allow to cool.
- Remove fiber.
- Rinse and either dye immediately or dry for later use.
Re-using the mordant bath
I found this in Rita Buchanan's A Dyer's Garden (which I like better than A Weaver's Garden, except it appears to be out of print. It's still available, but who in their right mind is going to pay that kind of price???) Anyway . . .
Because the fiber or yarn doesn't absorb all of the chemicals from the mordant bath, it's possible to re-use them by topping them off with additional chemicals.
- Use 1/3 the amount called for in the original recipe
- Follow all the procedure steps above.
Discarding the exhausted mordant bath
Potassium aluminum sulfate is commonly used as a soil conditioner for acid loving plants such as blueberries or azaleas. The spent mordant bath can be used to water any acid loving plant.
4 comments:
Leigh, you answered one of my questions (disposal of the mordant bath). The second is what is the purpose of the cream of tartar?
Excellent question, TB. The cream of tartar assists the take-up of the alum in animal fibers. That leaves less in the pot once the process is complete. So less waste and less to dispose of.
For plant fibers like cotton, tannin is used instead of cream of tartar.
I need to add that to this post. I'm working on a natural dyeing index page for my "study & workshop notes" because I like having all the important points easy to find for future reference.
Interesting and thank you! I am now wondering what the chemical process is that causes all this. A whole new world I had no idea existed.
It's extremely interesting, I agree. Archaeological evidence (based on analysis of textiles found in digs) suggests that the ancient Egyptians didn't use mordants (if I'm remembering correctly), but they were used in ancient Europe. Natural dyes fell out of favor when synthetics came a long because the results were more predictable. But half the fun is the surprise of what you get.
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