By Curtis Utley, Jackson County Extension
For our school’s Earth Day celebration this year I was asked to provide a t-shirt for the 4th-8th graders. Being interested in STEAM education I thought to myself “Hmm, instead of giving the students a shirt I will provide the necessary materials to make a shirt”.
|Application of blueberry blue with rubber mallet.|
For thousands of years mankind has used naturally occurring materials to dye the clothing worn. Some of the materials are earth minerals but many of the dyes used are derived from plants. Not all plant-based dyes are very stable, but stability can be increased by pre-treating the cloth with a mordant. I pre-treated the t-shirts with potassium aluminum sulfate otherwise known as Alum, you know, that stuff you can use to make your canned pickles crisp.
The dyes we used were mainly fruit and vegetable based including blueberries, cranberries, carrots, grape juice concentrate, tomato juice, and coffee.
|Application of Cranberry gray.|
Even in nature colors are chemical, but everything is chemical right? yellow, orange and red are derived from the plant’s production of carotenoids. As dyes, carotenoids are best mixed with an oil carrier to help fix the color. Purple, blue, and pinks are derived from anthocyanins. As dyes, anthocyanins can be mixed with water to create a liquid.
|Application of cherry red with rubber mallet.|
The best part of this project from the students’ perspective was the way in which we applied the colors to the t-shirts. Simple and brutish I let the students smash the fruit into the fabric with rubber mallets or paint their shirts with the liquid concentrates.