Cyanotype kit (ferric ammonium oxalate)

Description

Cyanotype on ferric ammonium oxalate — Mike Ware’s «new cyanotype». Shorter exposures, a wider tonal range and cleaner highlights than the classic formula.

What is better about it

Ferric oxalate is more light-sensitive than the citrate, so exposures shorten several-fold. More importantly the solution soaks deeper into the paper and holds a longer tonal scale: where classic cyanotype tends to block up the highlights, this keeps them separated.

What it costs you

It is fussier about paper and pH: an alkaline, carbonate-buffered sheet will ruin the print. The classic citrate kit is more forgiving, and easier to start with.

Questions and answers

Does it need different paper?

Preferably acidic or neutral cotton paper without a buffer. On alkaline paper the oxalate process loses density.