Primitive chemistry is an amusing diversion and sometimes the results are surprising. I have made about a dozen images using various primordial soups and raw emulsions. Recently when I was using black iris pigment for a paper emulsion (this makes an image similar to cyanotype but a violet colour..... exposure is measured in days) I applied a mild solution of neutral pH fixer and the image 'disappeared' and the experiment ended up forgotten on a table near a window..... rediscovered it a few days later and it had revealed a watery version of its former self in an ochre colour... and it is getting darker every day it basks in the sun. For me standardizing and optimizing is not the objective.... it is rather like a type of folk art where you end up with a enchanting 'photographic whirligig'.