Feeds:
Posts
Comments

Posts Tagged ‘dye’

Rabbitbrush, Ericameria nauseosa. The flowers make an excellent yellow dye.

Rabbitbrush, Ericameria nauseosa. The flowers make an excellent yellow dye.

Last September, in a conversation with our biology teacher, I learned that common rabbit brush makes an excellent yellow dye for natural fabrics. It was used by Native Americans and early pioneers to dye cotton, linen, and wool. I grew up thinking of rabbit brush as a useless scrub brush that grew in unused corners on our farm where the soil had high alkali or clay or low drainage. It is often seen along road cuts and other areas where the soil has been removed or disturbed, and is one of the first plants to colonize bare soil.

Rabbitbrush grows in poor soils and is one of the first plants to colonize disturbed areas.

Rabbitbrush grows in poor soils and is one of the first plants to colonize disturbed areas.

Intrigued by our conversation, I did some research. Its Latin name is Ericameria nauseosa for good reason: up close, the blossoms smell rather nauseating. In the early fall, it blooms with tight bundles of bright yellow flowers that can be steeped in boiling water and used for dye. I also found that it contains around 6% latex rubber in its stems and leaves to protect it from dehydrating. If a commercial method could be devised to extract the latex economically, it would be a valuable plant to grow and harvest. I had no idea.

Students prepare a dye bath of sunflower petals.

Students prepare a dye bath of sunflower petals.

I decided to try rabbit brush dye in my chemistry class. My course schedule for chemistry is already overflowing with more activities and labs than I can accommodate in our limited classroom time. To add a new activity would mean giving something else up. So adding a fabric dyeing lab would only be possible if I used the activity to fulfill more than one objective. I decided it would make a great inquiry lab to introduce the scientific method and meet Utah’s Intended Learning Outcome objectives. These ILOs include teaching the history and nature of science and the scientific method across all science courses.

Cloth soaking in a boiling dye bath made of rabbitbrush blossoms.

Cloth soaking in a boiling dye bath made of rabbitbrush blossoms.

I already had a number of large pieces of undyed fabric, including cotton, linen, silk, and polyester. I scrounged or ordered other types of dyestuffs, including walnut shells and cochineal. I cut the fabric into small swatches and purchased washing soda (sodium carbonate), cream of tartar, and other possible mordants. I also brought in a number of large pots from home.

Dye bath made from walnut shells. The original bath was the dark brown color seen with the shells, but it was accidentally thrown out. The second attempt was lighter.

Dye bath made from walnut shells. The original bath was the dark brown color seen with the shells, but it was accidentally thrown out. The second attempt was lighter.

On the first day of the activity, I introduced the process of science and the idea of variables and how to create an experimental design to control them. We then took a short field trip to a road embankment about ¼ mile from Walden School where a good stand of rabbit brush was growing. We collected several bags full of yellow blossoms. The students then divided into lab teams and designed their own experiments.

Samples of cochineal dye solutions. Cochineal is a sessile insect that lives on prickly pear cactus in Mexico and South America. It is collected, dried, and crushed to make carmine dye.

Samples of cochineal dye solutions. Cochineal is a sessile insect that lives on prickly pear cactus in Mexico and South America. It is collected, dried, and crushed to make carmine dye.

We boiled the rabbit brush blossoms, some black-eyed susan petals we collected along the way (commonly called sunflowers in Utah), and walnut shells in water. The cochineal shells were ground up in a mortar and pestle, releasing a deep burgundy liquid (carminic acid). The group that tested cochineal added varying amounts of tartaric acid to stabilize the color and create a brighter red. Each group tested both synthetic and natural fibers. Some groups tested mordants, which set the color by opening up the fabric fibers. Some groups tested different times in the dye bath, or different temperatures. In each case, they tried to test one variable and keep all the others constant.

Solutions of cochineal (carmine) dye. To create the different hues of red, tartaric acid was added.

Solutions of cochineal (carmine) dye. To create the different hues of red, tartaric acid was added.

The designing, preparation, boiling, and dyeing was done on our second day. It was a Friday before a long weekend, and we discovered an unanticipated variable. Leaving the cloth in the dye baths over the weekend resulted in mold growing in the water and on the cloth. One group testing the walnut shells accidentally dumped out their dye bath, which was a rich, deep brown. They had to start over using the same walnut shells, and the second time the color was much weaker. All of these problems and their effects were noted in the students’ lab notebooks.

The sunflower (Black-eyed Susan) dye bath turned brown when boiled. It also grew mold over the weekend.

The sunflower (Black-eyed Susan) dye bath turned brown when boiled. It also grew mold over the weekend.

After dyeing, we rinsed and dried the cloth swatches. One team took their swatches home and washed half of them several time in order to test the color fastness. In order to get numeric data that could be analyzed statistically, we compared the color by scanning the dried swatches into a computer and using the Eyedropper tool in Adobe Photoshop to click on three areas of each swatch, then record the RGB values and average them per swatch. The HSB values (Hue, Saturation, and Brightness) were also compared.

Finished swatches after dyeing and drying. The pink is cochineal, yellow is rabbitbrush, even tan is walnut, and uneven tan is sunflowers. Undyed cloth is also shown for a control.

Finished swatches after dyeing and drying. The pink is cochineal, yellow is rabbitbrush, even tan is walnut, and uneven tan is sunflowers. Undyed cloth is also shown for a control.

The students drew their own conclusions based on the variables they were controlling and wrote up the results in their lab books, answering a series of questions I gave them to help them consider what they had done. By the time we finished, we had spent about five days of class time, which was quite an investment but well worth it. We followed up by discussing how dyes are done commercially, other types of natural dyes such as indigo and madder root, and the invention of aniline dyes derived from coal tar such as Sir William Henry Perkin’s discovery of mauve dye in 1856.

William Henry Perkin, who discovered the first synthetic aniline dye (mauveine) at age 18 in 1856.

William Henry Perkin, who discovered the first synthetic aniline dye (mauveine) at age 18 in 1856.

Some notes for improving the lab for next time: I need to make sure we don’t leave the dyes over the weekend, and I want to use wool as a natural fiber in addition to cotton, linen, and silk. I tried looking for undyed and untreated wool, but the hobby stores only carry the mostly synthetic brands that are dyed white. Next time I will have to see if any of my students have access to natural wool yarn, or order it directly. I would like to dye untreated yarn in each color and crochet hats or scarves from it. I don’t want to mess with indigo, as that is quite a process, but I will order some madder root and other natural dyes.

A letter from William Henry Perkin, Jr. and  sample of silk cloth dyed with mauveine, the first aniline dye made from coal tar derivatives. It is a much brighter color than we usually associate with mauve today.

A letter from William Henry Perkin, Jr. and sample of silk cloth dyed with mauveine, the first aniline dye made from coal tar derivatives. It is a much brighter color than we usually associate with mauve today.

Finally, I would like to find a way to stabilize the dyes (perhaps by adding vinegar, etc.) so that mold won’t grow, then use the natural dyes for tie-dyed shirts. It would also be fun to make a dye out of purple cabbage juice, soak a cotton shirt in it, then treat it with squirt bottles containing mild acids and bases to change the color of the fabric like a pH strip, then set the colors by heat treating.

Advertisements

Read Full Post »

Walden School students at TImp Lodge near Sundance.

Walden School students at TImp Lodge near Sundance.

Each year in September we take all the students of Walden School of Liberal Arts up to Timp Lodge, a large cabin above Sundance Ski Resort owned and rented out by Brigham Young University. We rent it for a week and have the different grade levels take turns using it, with the high school using it for three days and two nights. We do this so that students can bond with teachers outside the regular classroom. By breaking up students in various workshops, we also hope to develop friendships between all the students and prevent cliques from forming. We do a variety of activities such as a 2-mile hike to Stewart Falls, workshops for the elementary students, a talent show, and a dance.

Walden School students inside Timp Lodge near Sundance.

Walden School students inside Timp Lodge near Sundance.

During our first day there, each teacher puts together a workshop that is both fun and educational. I had proposed to make Shrinky Dinks using the process I’d learned at the ASM materials science camp this summer, but not enough students signed up for it (I guess I need to come up with a better name . . .). One of our new part-time teachers, Austin, was trying to brainstorm some workshop ideas and I helped out, since he didn’t know what kinds of things would work. We came up with the idea of doing tie-dyed shirts. He had 30 students sign up, so I agreed to help out. Now why didn’t I think of that in the first place?

Wild turkeys at Timp Lodge near Sundance. And I'm not talking about students, either.

Wild turkeys at Timp Lodge near Sundance. And I’m not talking about students, either.

Since not all of the 30 could get around the tables and use the dye bottles at the same time, I came up with an additional idea to make marbled paper. I’ll describe this in my next post. But this time, lets talk tie-dye.

Hiking to Stewart Falls.

Hiking to Stewart Falls.

Austin purchased an assortment of standard Ritz dye colors and some plastic squirt bottles (such as used for catsup or mustard). We had the students bring their own shirts or other clothing items (some did socks, and one even did underwear), but we purchased extras for those who couldn’t bring their own. We also brought tubs and buckets for mixing the dye, plastic disposable tablecloths, large Ziploc bags, rubber bands, and washing soda as a mordant.

Squirt bottles full of fabric dye. We used yellow, orange, carmine, purple, blue, and cyan.

Squirt bottles full of fabric dye. We used yellow, orange, carmine, purple, blue, and cyan.

A mordant is a chemical that forms a coordination complex with the dye molecule so that it can attach permanently to the fabric substrate, such as wool or cotton fibers. As for any pigment, for the color to last, it must be insoluble in water, yet the dye itself must be soluble in water when first mixed. The mordant forms a “lake” (from the old Latin “lac” from which the word shellac is also derived) that makes the dye insoluble and permanent. The mordant is usually a metal ion salt that forms a base in solution, such as washing soda (sodium carbonate). Other common mordants used historically include urea, tannic acid, aluminum salts such as alum (aluminum phosphate), and even salt (sodium chloride). I would like to do this in a more controlled setting sometime to test the effectiveness of different types of mordants.

Method for making a bulls-eye pattern. The center is pulled up while the shirt is twisted slightly, then bound in sections by rubber bands and dyed.

Method for making a bulls-eye pattern. The center is pulled up while the shirt is twisted slightly, then bound in sections by rubber bands and dyed.

Our procedure was to mix the washing soda into a bucket of water and soak the T-shirts in it for several minutes. We then spread them out on the plastic tablecloths and folded them to produce one of several patterns. For example, you can make a spiral design by taking the center point and pinching the cloth, then twisting the whole shirt into a spiral and tying it together with rubber bands around the outside and across the center. The dyes are then squirted onto the rolled up shirt to form wedges of color, overlapping them to make gradients. We discovered that you get more color if you really saturate the dye in the wedges, going over them several times and even squirting some in between the cracks and ridges so that color gets down deep and leaves less white.

Ziploc bags full of dyed T-shirts. The dye was allowed to set before air drying.

Ziploc bags full of dyed T-shirts. The dye was allowed to set before air drying.

To make bulls-eyes, choose the center and pull it up while twisting to make a long rope, then attach rubber bands at intervals to hold the cloth together. Squirt different colors of dye between the rubber bands. Where the rubber bands are pinching the cloth together, less dye will penetrate and will leave white rings separating the bands of color.

Drying T-shirts at Timp Lodge.

Drying T-shirts at Timp Lodge.

To make tiger stripes, lay out the T-shirt face up, then drag your finger from one shoulder diagonally down to the opposite corner, creating a pleated fold that is then held together by rubber bands. Bands of dye color are squirted along it. To make a plaid pattern, take the tiger striped pattern and make a second set of accordion-style pleats.

Plaid, spots, and spiral patterns.

Plaid, spots, and spiral patterns.

We had enough T-shirts that I tried several different patterns to see which were best. I liked all the results, especially the tiger stripes. I think I would create a gradient of colors (say yellow through orange to red) across an unfolded shirt, then fold it and make a second set of colors (blues and greens). That way, interesting color combinations would result and there wouldn’t be any undyed white areas. Or I could do two different patterns on each shirt, letting them dry in between. I will have to do more experimentation.

Tie-dyed shirts showing different patterns.

Tie-dyed shirts showing different patterns.

After applying the dye, the students sealed the shirts in Ziploc bags for several hours to allow the dye to set, then gently washed the soda out. They then let the shirts dry completely in the sun. I told them the color would be fast (permanent) if they heat set it by running the shirt through a drier before washing it. It remains to be seen just how color fast our T-shirts are. The ones I’ve made have held up pretty well.

Fall 2014 tie dye samples

A sampler of shirts, socks, and scarves dyed in my 2014 Timp Lodge workshop.

We had T-shirts drying all over the place on the Lodge’s railings and many turned out quite well. For the next several days after we returned from Timp Lodge we had quite the tie-dye fashion show as students wore their shirts to school. We’ve had the reputation of being “that hippie school” in the past, so I suppose this helps verify our image.

Star shirt

Yours truly wearing a star patterned shirt. I’m running out of white T-shirts, so I’ve been using whatever I can for practice.

Update to Post for Fall, 2015: 

I have continued the tie dye class at our annual Timp Lodge retreat for three years now. Looking at the photos shown above, I can see we’ve made some progress. The main difference has been introducing a better type of dye. Instead of the Ritz dyes you buy at a grocery store, which create the weak colors seen above, I ordered Procion MX dyes from Dharma Trading Company and the results have been much more spectacular. I have even re-dyed some of the shirts from 2013 just to get better results.

Double spiral shirt

I found a nice long-sleeved white shirt at a local store and dyed it into a double-spiral pattern. It didn’t work as well as I’d hoped, but the colors are fun. You can see that the Procion MX dyes are much more intense than the standard Ritz colors.

I’ve learned how to make several advanced patterns, such as stars (you fold the shirt in an origami pattern similar to a paper airplane and tie it off using chopsticks and rubber bands), double spirals, and even Taoist Yin-Yang symbols, which involve sewing in lines of thread that can be pulled to gather the cloth in a specific pattern of S-curves and circles.

Dao shirt

I was attempting to make a Taoist Yin-Yang symbol by gathering the shirt along an S-shaped curve with two circles. It didn’t quite work, but the colors turned out well.

I have standardized the student samples by purchasing white wash cloths and towels for the students to use instead of relying on them to remember to bring T-shirts or whatever.

Becca spiral shirt

My wife, ‘Becca, wearing a standard spiral pattern I made for her. This one turned out nicely.

Towels

Some sample towels and dishcloths I did at Timp Lodge.

In other words, I have this fun art form down to practically a science. The only problem is that I now have so many tie dye items, its come to dominate my wardrobe! I even have tie-dyed socks and shorts.

Dao towell

This towel shows the Yin-Yang symbol pattern much more clearly, although I didn’t plan out the colors very well.

Spiral towell

A classic spiral pattern on a white towel.

Read Full Post »