Bob,
Saw your presentation and prints at APIS in Santa Fe last week (and the 2013 presentation, too). Regarding papers suitable for uranotype: I believe you might be too quick to dismiss the papers you tested (Hanhemuhle, Revere, Platine, Crane Cover, COT320). None of the test prints in your video displays any of the failures one generally sees with incompatible papers like staining, weak image, etc. I don't print uranotypes, but I do have extensive experience printing platinum/palladium, salt, and albumen. It can happen, but I wouldn't expect different papers to achieve identical results without optimizing the workflow since the paper chemistry participates in the process. This means for each paper:
- deriving the base exposure (minimum exposure required for dmax) for a given drop count, including Tween and other additives.
- modifying the digital negative density to achieve paper white at your derived base exposure
- deriving a correction curve to linearize the digital negative for the appropriate tonal separation
- maybe including toning in your testing
It would be helpful to know the dmax of your digital negatives, what density you find optimal for uranotypes, and the method you use for creating digital negatives. Will you get clean, paper white borders if you mask the negative when printing?
