Life of prepared cyanotype papers

Common wisdom says to use traditional yellow-type paper as soon as possible after it has been prepared. And certainly, you will get the best results from that.

However, do not be dissuaded from using older paper. Last April I ran a workshop on building cyanotype cameras, and I had a bunch of kits left over. Today I pulled out some of the papers, and did some contact print test exposures.

Pleasingly, despite being quite discoloured when unexposed, they exposed perfectly well, even with a very low contrast negative.

So even after nine months, a well prepared paper with is still perfectly usable! This makes stockpiling for trips a much more plausible thing!

On the left is a 20 minute exposure, and 10 minute on the right. The negative is notably low-contrast.

As you can see, fully exposed areas still give excellent density, and the unexposed areas have nearly washed clean, with only a little residual staining.