13. Mar, 2019

The Amazing Thing About Tannin

In this round of experiments on silk I got some very hohum results from fresh leaves that I thought would give good results - I have always believed eco printing on silk was easier than on cotton. So why would the prints be not so good. Then I took some dried leaves from last Autumn and rehydrated them. I had good results on cotton with these leaves and I was not disappointed on the silk either. So why was there such a difference? I thought about how the colour changes from Sprint to Autumn on the same leaves from the same tree and then I did some google searching. It seems in Spring the young tree/plant shoots are higher in tannin which makes them more bitter and protects against being eaten until the tree is well established. As Summer comes on tannin levels drop and then as Autumn gets here and the chlorophyll levels drop (causing the colours of Autumn leaves) the percentage of tannin in the leaves goes up again. I havent found this in any one document but have read various articles (some of them very scientific). My summation is that it is the level of the tannin that is responsible. I do know the use of tannin on cellulose fibre is a necessary precursor to alum to get good prints and that the leaves that print best are usually high in tannin. It is an interesting concept and I will try and do more research on this when and if I have time. In the meantime I am delighted that my nearly year old dried leaves have left such clear impressions