I'm teaching some alt process to my HS seniors and I may have created a monster. I have a guy who wants to explore printing on glass and stacking the images in front of a light box, and he's read that casein sticks better to glass than plain gum. And in fact, gum just washed off in my experiments.
Does anyone have any thoughts on how to proceed with this? I'd be grateful.
Come on, Holly. You create monsters all the time!
In terms of the glass, it may be difficult with casein, which is not really transparent. If you could work with acetate, there is a prepared acetate that takes water-based work. I don't know how it would fare in the processing though. It's called (unimaginatively) Prepared Acetate.
For gumprinting I would use a gum "primer" layer without negative but hardened with UV light and fully developed followed by one or several gum layers with negative. Gum should not wash away on glass there even was a photo mechanical process called the Erwinotype/Erwinotypie that used glass with a gum matrix as printing plate. Look it up it really is an interesting process. For casein print I would use a sublayer of hardened casein just like with gum.
For gumprinting I would use a gum "primer" layer without negative but hardened with UV light and fully developed followed by one or several gum layers with negative. Gum should not wash away on glass there even was a photo mechanical process called the Erwinotype/Erwinotypie that used glass with a gum matrix as printing plate. Look it up it really is an interesting process. For casein print I would use a sublayer of hardened casein just like with gum.
"Barkeepers' Friend" does an excellent job of cleaning glass.
You might want to try subbing your glass with a weak (1%) gelatin and chrome alum solution. Let it harden for a few days and it will provide a very durable subbing.