Saturday, April 23, 2011

Red Sandalwood Powder and Final Thoughts on Mordant Concentration Experiment

Another Indian dye that we tested this winter was red sandalwood....I am very fond of this wood for a few different reasons....First of all it offers a wide range of pinks, corals, and salmon shades....But my main attraction is the emotional attachment that Dominique and I developed to sandalwood and red sandalwood while living in Mysore. This proud city in Karnataka used to be the sandalwood capital of the world....Today the sandalwood forest are gone, and when I think of them from time to time, remember the smell of sandal smoke rising from burning charcoal, or read stories of small idyllic ashrams nestled in pristine sandal forest, and not being able to experience them, I do get the occasional sandalwood blues....

Sandalwood cultivation, processing and export are tightly controlled by the Indian gov't. In this case I am not sure if this involvement is a part of the solution or the problem causing the scarcity and the very high prices.

Red sandal which is related to real, yellow, sandal by name alone and nothing else is extensively used in ayurvedic medicine. It does not yield to the chisel and the hammer as gracefully as sandalwood, but all the sandal carving workshops also work with this wood, mainly for their marquetry pieces. It is also used as a dye. Though in retrospect I must say that it is not very light fast, and would recommend using madder or other more readily replenishable natural dyeing resources to get some of these colors.

Back to the the subject at hand. Just as with all the other dyes in this experiment we did a hot bath and a cold bath. The colors we obtained from both were basically the same, so I will only post the results for the hot baths, but will use the cold or solar process in our production dyeing, subject to the results of light fastness tests.

First unmordanted local wool.

Since presently we are running new experiments this will probably be my last post on the mordant concentration tests that we ran this winter. I will try to summarize what I have learned from this rather tedious and long adventure. Also, I am leaving out the concentrations here, but they follow similar patterns to those illustrated in previous postings.

First of all alum. From the perspective of bright colors, it is my favorite mordant next to tin, but of course it is much easier on the fibers. I am just a bit concerned about its light fastness esp. with.yellow. (It is about a month since we hung the samples outside for our tests, and yes sun giveth, but it doth also taketh away.)

In the majority of cases the 25% straight alum gave me the best results and I will try to use this concentration in our production work. Addition of CoT has a favorable effect on the fiber quality, but sometimes dulls the color and generally limits the color range. In general the addition CoT gives pastel tones, some of which can be very interesting in their own right. When I run future tests on new dyes I will most likely use two concentrations of alum, pure at 25 and 10/2 with CoT. Of course all of this and further observations are still subject to the light fastness results. Different concentrations of alum can often give striking results. But this varies from dye to dye and in case of red sandal the differences were minimal.

Red Sandal on copper. Before I undertook this journey into mordants copper was my favorite. I am very partial to deep-earthly tones, the shades of autumn leaves, the colors of olives, and things of that nature. In this department copper is king. Sometimes, when it muddles the colors too much it disappoints me. Thankfully it does not happen too often. One of the more pleasant surprises is how it deepens some of the lighter dyes, like the yellow of pomegranate and berberis (that did not appeal to me originally, but I have grown to appreciate as I was looking over the samples). I prefer copper at lower concentrations and in the near future will stick with two variations: 2% pure and a 2% with addition of acetic acid. I am still not convinced about the roles of the assistants here, but will continue to experiment with them for the time being. Out of the 4 mordants we tested this time, copper I think showed the least response to mordant concentration and assistants.

Red sandal on iron. Best for dark grays, brown, violets, etc...but does give interesting results on light dyes as well. Not always, but often, the different concentrations result in different colors. This is a good example. I was a bit perplexed by the fact that my assistants (CoT and sodium sulfate) showed more fiber damage than straight iron and will have to study the effects of assistants on this mordant in more detail as well.

Iron and tin were the two mordants that surprised me the most during this round of tests. They both left a unique set of questions that I plan to pursue in future tests. In case of iron it is the difference in color that different concentrations produce. It is probably fair to say that iron will give deeper and darker tones in proportion to concentration, regardless the dye material used. Our tests went up to 4% (this is considered high). This level gave us quite a few 'midnight' tones of bronze, violet, purple, brown, burgundy, gray, etc...but nothing approaching the elusive black on wool. One of our future experiments will involve further work with iron and dark organic mordants, with black color (on wool) and fiber stability in mind. If anyone has any suggestions along those lines, they would be welcomed.

When I included tin in these test, it was mainly out of curiosity without any intention of using it in production work. But for better or worse I fell in love with the intense colors that it can produce. Often, but not always as the case of red sandal demonstrates, they are stronger than the ones offered with alum. Some of the best yellows, pinks, oranges, etc...were captured by tin. I am still awaiting the fastness results with great anticipation. From what I can see already, some of these colors are fading, but many seem to persist.

Tin like iron and alum is responsive to mordant concentrations, and in the near future we will use two concentration. In most probability 2% and 8%. It was also pointed out that tin works best in the dye bath itself and not as a premordant. This we still have to try.

The biggest problem posed by tin is its effect on fiber stability. It was with tin in mind that we undertook our next round of tests. They are supposed to give us a better idea of relationship between temperature/duration and effects of mordants on fiber structure. Presently we are running mordanting experiments with solar baths, vat baths and hot baths at different temperatures and durations...

So this is it! We tested 5 other dyes with very similar results as the examples I described previously.

Was it worth it? I did not keep track of how long it took us to spin and ply the wool, to make a few thousand baby skeins, prepare over 30 mordant baths and another 30 dye baths. But I estimate that it would take one person 2 to 3 months of full-time commitment. In our case, where we are planning to start our production dyeing this year or at the very latest next year, it was a well rewarded effort, which I believe will save us lots of heartache and disappointments in the future. Or at the very least, it will limit them considerably.

Our original question was to determine whether it is worthwhile to use different mordant concentrations and assistant partnerships or just to stick with the proven formulas. I think we got a clear answer to this and will continue to experiment with each mordant in at least two (in some cases more) concentrations. Mordant concentrations and assistant partnerships do make a difference on the final color, fiber structure, the coloring capacity of a dye, and possibly light fastness. So we will continue to run these tests, in small batches, with all new dyes and local plants that we use...

Of course every answer we received brought with it new questions. Possibly these questions represent the biggest reward, as we pursue them in the future....


  1. Amazing study! You have given the natural dye community such a valuable amount of mordant information. Thank you. -- Bjo

  2. thanks bjo,
    we are still continuing with it from different perspectives.

  3. Hi! This was most helpful, I am linking back to this post (having tried sandalwood myself), I am at : Thanks!!