Emulsion peeling off glass negatives 1920's

[Ramiro Elena]

I don't know much about glass negatives so I was surprised to see a set of 13x18 glass negatives from the 1920s at my friends' house in which the emulsion was peeling off in one piece. The emulsion is brittle but it doesn't brake if handled with care.
Is this something common?
Any recommendation as to how to take care of them? I imagine the emulsion will not stick back to the glass.

Thank you!

[jp]

It's pretty common.

I think some people recycled commercial dry plates when their photos were a fail and coated them themselves and you see this. I suppose it could be an inferior commercial plate.
Officially the archival thing to do is "no harm" and just don't handle them or allow further damage.

On wet plates when I had some emulsion peeling, I was able to affix it back to the glass with some egg whites on a q-tip to recoat the glass and then the emulsion to soften the emulsion and it lays back down to dry. I suppose this would work for old negatives as well.

[Nodda Duma]

Getting the emulsion to stick properly to glass is *the* biggest challenge to overcome in making dry plates. The effort I expend on cleaning and prepping the glass for good adhesion far exceeds the effort on actually coating...even as much as I’ve automated my cleaning and prepping process.

That was as true then as it is today.

[Ramiro Elena]

Great! Thanks for the info. I will explain to my friend.

[Jim Jones]

If the images are valuable, scan those negatives.