Quote Originally Posted by Dracotype
I don't mean to butt in, but Mike Ware does explain the ferric process on his website. I seem to recall, that Fe3+ reduces only in the presence of UV light, not regular light. In lieu of any materials on the C. rex process, I would lean on previous scientific data. Actually, Hershel did try ferric ammonium citrate by itself, and developed in various things (including potassium ferricyanide and gallic acid). His conclusion was that the citrate by itself was too slow. Oxalate might be a different story. And don't get me wrong. If the cyanotype process was faster this way, I would be near the front of the line on getting at it. But I also think that both Herschel and Ware have researched the cyanotype very thouroughly. I don't mean any of this in a mean way, just disseminating info. No hard feelings?

The Unblinking Eye has a variation on the cyanotype with gallic acid if I remember rightly.
Drew, what you're saying above is the accepted wisdom on iron-based processes, no question. It was in examining how Herschel originally did his prints (coating the sensitive iron alone, then developing with the colorant) that the current workers came to the rex processes; beyond that, I'm only repeating the claims they've made. I haven't done it yet -- perhaps in the next day or two, having completed my camera repair and conversion work today.

HTML, waxing paper negatives (from the back) was standard practice for decades, back when kallitypes in camera were competing with Daguerreotypes. It *might* be possible to coat c. rex on inkjet transparency material -- certainly worth trying, I'll have to see if I have a box of that stuff around the house. Those who created c. rex report being able to contact print from c. rex negatives back to a positive in the same medium, but (again) haven't published whether they waxed the original or otherwise rendered it translucent.