For some weeks now I have been struggling with gumbichromate and it has given me some gum(sad) time. Here, sharing with you some experiences and lessons learnt.
In the process of gum bichromate we uses,
- Potassium or ammonium bichromate
- Gum Arabic or Gum acacia powder.
- Water color paste.
Though this looks very simple, so as I thought but there are different variables which makes this process stubborn. I started off this process as recommended by http://www.alternativephotography.com but the result was far from satisfactory. While I started off with 30% solution of gum acacia to 10% solution of potassium bichromate. Initially I got some faded images which when exposed in sun 30 to 45 min.
Till this time I couldn’t figure out the problem.
After this I tried this process on various kinds of papers and instead of distilled water i was using normal tap water. The time it was taking for printing was very long like one and half hours under sunlight and the impression was faint. Here while washing , I was using the brush rigorously, hence you can see some scratch on some prints.
In the next phase the distilled water was used and UV light was fixed. Meanwhile Shreyasi Kar visited us. She made a good print using 1:2 ratio of potassium dichromate to gum. Her exposure time was two min in sun. Now I tried repeating the process under UV light.
One important lesson I got here is distilled water and a good water color paper makes a huge difference. Third phase will be in the next blog.