Indigo dyed paper
As an experiment, I included dyeing paper with indigo as one of the activities in the Persian and Indian manuscript painting workshop this month. With only two (highly sophisticated) people, it seemed a good time to indulge in some fun. Indigo dyeing is a very messy process, but also very fascinating, as it behaves like no other dye. It is mostly associated with textile dyeing – usually cotton – but it can work well with the right type of paper. The paper needs to be a good quality rag paper for it to work properly – cheaper stuff will simply disintegrate in the dyebath. Manuscript and album pages in the 16th century and later were often coloured with indigo, but I think in most cases it was brushed onto the paper, as opposed to immersing the paper in the dyebath as I like to do. Natural indigo from the plant poses many challenges, so I choose to use synthetic indigo grains. They literally are a synthesis of the natural chemicals found in various species of indigo plants, and consequently react in the same way. I get my materials from Kemtex Educational Supplies where I can also get recipes and a lot of valuable advice about the chemistry of the process.
The first thing you need to do is to make a stock solution in a strong glass or ceramic jug according to instructions from Kemtex, and be sure to follow their health and safety advice. The stock solution is basically a strong alkaline solution to which a de-oxygenating agent is introduced, before adding the indigo grains. You can see the stock solution here before all the ingredients have been stirred and dissolved. The idea is to remove the oxygen from the water so that the indigo can react with the paper before it is exposed to the air. Once the stock solution has been prepared it is gently introduced to the dyebath, and allowed to stand for about twenty minutes. The liquid will be clear and yellowish, and forms a thin metallic looking scum on top – that is the indigo on the surface reacting to oxygen in the air.
A test strip is immersed for a few seconds into the dyebath to check that it is working properly – and here you begin to see the magic. The paper comes out bright yellow! Over the next few minutes, as the dye reacts with the oxygen in the air, it turns before your eyes through shades of turquoise, then green, until it finally becomes blue, with a deep metallic purplish patina.
The first immersion gives you a fairly light blue. If you want darker shades you have to wait untill the reaction has fully completed, then re-immerse it for about thirty seconds and take it out again to react with the air.
A really deep blue requires about eight immersions. It works better if you rinse the paper thoroughly after each immersion, though that creates a hideous mess as you carry sheets dripping with dye to and from the nearest sink. As you progress, the dyebath becomes weaker as oxygen gradually seeps into the solution, so you need to keep adding more ‘Hydros’ – the de-oxygenating agent. I might add that the whole thing is so smelly it can make you gag!
Here is the end result after several hours of involvement – not to mention a whole night devoted to cleaning up the mess! Not the most practical idea for a workshop, but what a fabulous result.