A student of mine tried a couple of Pellet Process formulas which I did
not encourage and which didn't work anyway....
I did not encourage him because it seemed to offer no advantage (if you
want a picture in white on blue ground, print your positive, if you don't
have a positive make one make in about 3 minutes with 30 cents worth of
lith film) and a serious disadvantage -- it uses MUCH more chemistry than
cyanotype, the solutions being much more concentrated, and, as I recall,
it has at least one extra step, a final "development" in, was it potassium
ferricyanide? Feh!
Judy