I think it is time to reanimate this old fantastic thread:

Diazo/DAS is also used replace dichromate in Collotype:

http://www.phototypie.fr/wordpress/e...s-bichromates/

The side contains a nice description about Collotype.

For the carbon print: I tried for long time to sensitize coated gelatin layers with a brush. This works in principle even with the Speedball sensitizer. However I always get some degree of fog. (Even on the unexposed parts of the gelatin layer). So I add the DAS now to the gelatin before coating.

Many thanks to Chris for making the DAS available. Since Iíve access to a photo spectrometer I made some absorption spectrum of DAS in water. It has a maximum around 333nm.