The Proof is in the Pudding

As some of you know, this spring we ran a few experiments on mordant concentrations and Indian natural dyes. In the scope of this project we included a simple and limited color-fastness test to get a general idea of how some of these dyes react to light, water and other environmental factors, but mainly to find out how to construct any future tests of such nature.

The first part of this project included a wash-fastness test. We hand washed each batch of skeins from 3 to 10 times to see if there was any bleeding. The only evident problem we ran into here was tesu or butea, which in most cases showed obvious bleeding even after many washes. The other dyes seemed to be wash-fast. As will become evident later I am a bit skeptical about these results, esp. in regards to lighter colors. 

The light-fastness test was performed by applying a 2 inch section of tape on each skein and hanging it outside for over 6 weeks. In most probability this period was unnecessarily long, but since it was our first major, semi-organized attempt at this we took it to the extreme. Weather cooperated, providing us with snow, rain, hail and scorching sun.

The first observation I want to mention is that both madder and indigo are extremely fast. In both cases there was very little change in color even after such an extended and rough test period. Both of these dyes stood head and shoulder above all the other substances we tested and can serve as the ideal benchmarks. I will not post any pictures of these two yet since we are in the process of running more comprehensive tests the results of which I will post in a few months at which time I will dedicate a full post to each of these important dyes.

Here I would like to concentrate on selected negative results and some rather odd things that we noticed.

Let’s start with berberis strta with alum. This one gave us beautiful yellows, which unfortunately show strong light-fastness issues. I am still not giving up on this one, and we will continue to experiment with it under different conditions. We will also look into some of the local species of berberis, which grow here in great abundance.

Berberis with copper shows the same light-fastness issues as alum.

Berberis with iron, showed slightly better results in most concentrations of iron. They are nevertheless still unacceptable.

Berberis with tin. Same, same....and they were such nice colors....oh, how the heart aches.

Let’s go on to butea. This one is quite interesting and I will illustrate both hot and cold bath examples. In this particular cold bath we used a very high ratio of dye to fiber. I think it was about 3 to 1. The colors of the cold bath are therefore considerably stronger than the ones of the hot bath.

First of all butea with alum in a cold bath. What shocking results. We scratched our heads over this one for hours, hoping that we mixed up the dye batches. And even though it looks like a mix up I am pretty certain that it is just the effect of water and light on butea, but in this particular case mainly water. Butea and alum are definitely not wash-fast, and since all the color washed out with the rain it is hard to determine whether they are light-fast or not. I guess that last question is absurd.

One thing we noticed during the course of these tests is that it is very difficult to observe wash fastness results on light dyes when the tests are performed manually and the senses are the only measuring tools. The light colors tend to leech out slowly and are hard to observe. But when the yarns are left out to hang in the rain for longer periods of time any wash-fastness problem also becomes evident. In this case the color change occurs in the areas of the skeins exposed to the sun as well as in the areas covered by the tape. Butea on alum is a very good example of this, but there were many others. In parts of the world where rain is abundant and longer test periods are used, a separate wash-fastness test might be redundant. In case this is not feasible I would let the skeins soak in soapy water for about a week. With occasional turning this should give a good wash-fastness indication.

Butea cold bath with copper. Generally the same results as those obtained with alum.

Butea cold bath with tin. For few different reasons, this was really a pleasant surprise. First of all I love this orange color and would have been disappointed if I could not use it for production work. Secondly, and this is only a broad generalization, tin is probably the weakest of the four mordants we have used, followed by alum, and copper and iron. But in the case of butea it turned out to be the strongest.

There are still fastness problems here, but some of the tin concentrations are approaching an acceptable level. It is worth pointing out that in case of tin the cold bath gave much better fastness results than the hot one below. This poses new questions which we will try to address in future tests on butea.

Butea hot bath with alum. Same problems as above.

Butea and copper...same...same....

Butea hot bath and tin....same...but different than the ones we obtained with a cold bath, and warrants another set of tests...which we are running now.

Oak galls cold bath will be the final example that I will illustrate here.

Oak galls cold bath and alum. Please excuse, but the tested and non-tested sides labels have been reversed in the picture.

Not great, but better than the average of our fastness tests.

With copper. Same problems as above, and again the labels are reversed.

Oak galls cold bath and iron, showed rather nice results. This is a good example of what I would consider a barely acceptable dye. It is still a far stretch from the results we obtained with madder and indigo.

In closing, natural dyeing can be fun and produce beautiful results, but before one goes ahead and puts a skein of good yarn into a bath of a local weed or bark, or even into a bath of a known dye substance described in literature, it is wise to test a small sample and wait a month or so to see how the beautiful yellow or violet will really turn out. This is especially true for anyone involved in production work for resale. Having had some retail experience with naturally (and otherwise) dyed garments, I can fairly say that few things are as heartbreaking as colors fading before one’s eyes because they have been exposed to occasional sunlight. (Ultimately it is due to this past experience why I am sitting here typing out these notes.) In the end it is the customer who pays for all mistakes. So it is good karma to test, test and retest....

That’s it for now. Presently we are running new tests on the effects of mordanting and dyeing durations for three types of baths: hot, vat and solar. This test will be followed by a detailed light-fastness test on all of the dyed yarns. I hope to share these results in the future.