Dry plate tintypes from Paris

These are actually just liquid AG Plus emulsion on tin 4x5 sheets, so technically not the original process. This batch was fairly problematic despite the relative ease of the process compared to wet plate collodian. The negatives are created on Pictorico OHP with a custom curve generated by the ChartThrob plugin for Photoshop, and then contact printed against the coated plates.

The first 8 plates I coated had trouble with opposite edge run off when I was pouring excess emulsion off the plate. The areas that ran thin developed color bands with a titanium look. The thicker areas were fine, with an overall smooth surface and good exposure. To eliminate the thin areas, I let the run off cascade back over the coated plate to the other edge, then dumped the excess. This left a nice even coat across the whole face while drying, but after developing and fixing the plate surface became incredibly wavy, as you can see above. I though this was due to my re-coating with the run-off, but the next batch I coated only had one pass of the emulsion, but exhibited the same surface defects. I suspect that either the emulsion went through too many heat cycles at too high of a temperature before coating, somehow I contaminated the emulsion during the recovery of run off, or the black bottle it comes in is not light tight. 

Another thing to note is that my exposure times became exponentially long each time I coated a new batch of plates. Day one exposure was 5 seconds @ f/8, two days later it was 14 seconds @f/5.6, and two days after that it was approaching 30 seconds @ f/5.6. This leads me to believe it was indeed a problem with the emulsion after the second day that led to the increased exposures and the surface defects. While the plates did not see a refrigerator immediately after coating to set the emulsion, they did get light cool air from a hair dryer for a minute, laying flat.