pickling recipes as a preservative and to maintain crispness. It is approved by the U.S. Food and Drug Administration as a food additive, and is safe to use as a mordant with natural dyes in your classroom.


Pre-treating with Alum as a Mordant If a dyestuff needs a mordant, treatment can be done before-


hand and then dried and stored for dyeing at a later date. Alternatively, you can use the wet fibers right away. 1. Weigh the fibre to be pre-treated. 2. Soak the clean fibre overnight. 3. Prepare a solution of food-grade alum (1g of alum dis- solved in 10ml of boiling water). Stir the solution until all alum is dissolved. This solution can be added to the wet textile according to the pre-measured weight. For 100g of fibre you need 8g of alum or 80ml of pre-prepared solution.


4. When using alum, it is beneficial to add cream of tartar. This softens the fibre and aids in the absorption of the alum. Add 1½ tsp cream of tartar for 100g of fibre.


5. Fill a stainless steel pot with cool water (about 3 to 4L per 100g of fibre). Add alum and cream of tartar solu- tions and stir to dissolve. Add wet fibre and slowly heat to a low simmer. Simmer gently without agitation for one hour. Turn off the heat and let the fibre cool in the pot, gently stirring occasionally. When cool, remove fibre and rinse gently in cool water.


6. After the fibre has been pre-treated with alum and cream of tartar, you can add it to a dyepot or dry it and store for another time.


7. Disposal of diluted alum and cream of tartar in standard waste disposal systems is considered safe in most juris- dictions but it would be prudent to check the local situa- tion before disposing.


Safety Guidelines 1. Use rubber gloves, an apron and protective eyewear. If


handling hot pots, use oven mitts. The teacher should closely supervise any activity involving hot pots and liquids.


2. Work in a well-ventilated area. If available, the outdoors may be the best laboratory.


3. Keep the dyeing materials away from food. Use a dedi- cated dye pot. Do not eat or drink while handling dye- stuffs. Even some natural materials (i.e. rhubarb leaves) can be toxic.


4. If you handle powdered dyestuffs, use a mask and eye protection. Even though the alum mordant is safe to be ingested, it will irritate breathing passages and eyes.


Common Dyestuffs to Try Students can be encouraged to experiment with many safe


dyestuffs collected in the field, forest, garden or kitchen compost. The following have been tested and will produce natural dyes. • Common yarrow (Achillea millefolium) is a hardy perennial. The plant tops (including flowers) can be used either fresh or dried to produce a soft, yellow colour in fibres which have been pre-treated with alum and cream of tartar mordant.


• Hollyhocks (Alcea rosea) are common garden plants. Page 32


Dark hollyhock flowers may produce pinks or maroons on animal-based fibres which have been pre-treated with alum and cream of tartar mordant.


• Birch trees (Betula spp.) have been used for dying for centuries. Their leaves can be collected from early to late summer. With animal-based fibres which have been pre- treated with alum and cream of tartar mordant the result- ing colour will range from yellow to green. When using birch bark on the other hand, the fibre does not need to be pre-treated because the tannins act as a mordant. The bark should be harvested as shed material on the ground or peeled from cut branches. Avoid removing bark from the main part of the tree to avoid damaging the tree. Treat the bark as described above and use the resulting dyebath to dye wet fibre. Colours from birch bark are usually shades of pink.


• Skin of the common kitchen onion (Allium cepa) will produce a natural dye ranging from yellow, to orange, to rust, to brown. Onion skins are one of the most reli- able and versatile dyestuffs. Dyeing with onion skins is a great classroom activity that will introduce young stu- dents to the possibilities of working with colours derived from plants.


Where you go from here is up to you and your young


scientists/artisans. Experimenting with various dyestuffs to achieve interesting colours and patterns will help your charges to develop an artist’s eye and a scientist’s curios- ity. This is a solid base for inquiry-based learning. Planting a dyeing garden may ignite a passion for botany and hor- ticulture, something that often emerges in schoolyard gar- dening projects. Imagine the engagement that will emerge in a student who follows through on a journey that started with planting a seed and ended with designing and dyeing a unique t-shirt admired by all of his/her classmates. The learning possibilities are almost limitless.


Annamarie Hatcher teaches Integrative Science at Cape Breton University in Sydney, Nova Scotia. Her courses are imbedded in the geology and ecology of the natural envi- ronments of Cape Breton. This article stems from this back- ground blended with her hobby of handspinning wool fibres for locally-sourced textiles. The author would like to thank Rod and Claire Beresford for testing and visually document- ing the onion skin dyeing procedure.


Resources


Casselman, K. D., 1993. Craft of the Dyer: Colour from Plants and Lichens, Dover Publications; 2nd Revised ed. Edition, 272 pp.


Casselman, K.D., 2011. Lichen Dyes: The New Source Book, Dover Publica- tions; 2nd Rev ed. Edition, 96 pp.


Dean, J. & Casselman, K.D., 2010. Wild Color: The Complete Guide to Making and Using Natural Dyes Paperback , Potter Craft, 144 pp.


Vejar, K., 2015. The Modern Natural Dyer: A Comprehensive Guide to Dyeing Silk, Wool, Linen and Cotton at Home, Harry N. Adams, 192 pp.


McLaughlin, C., 2014. A Garden to Dye For: How to Use Plants from the Gar- den to Create Natural Colors for Fabrics & Fibers, St. Lynn’s Press, 160 pp.


Notes 1. Tanaka, M., 2016. Learning and Teaching Together. UBC Press, Vancouver, 236 pages.


2. Dean, J., 2010. Wild Color: The Complete Guide to Making and Using Natu- ral Dyes. Watson-Guptill, New York, 144 pages.


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