Really old Photo plates - are these still any good?

[htmlguru4242]

I found an old box of Wratten & Wainwright "Wratten M Plates" on EBay the other day for a decent price, so of course I bought them.

I really bought these for the box and the glass, but me being me, i got to thinking if these might be any good still. From the looks of the box, they expired in the early 1940s at the latest.

Anybody have ideas as far as exposure, development times, are these ortho or pan? Any chance that these are not completely fogged to hell?

Surprisingly, the internet has failed me so far at finding any specifics.

 

[bdial]

They are probably earlier than the 40's even, from the look of the box, more like teens or 20's, IMO.
If the box is not sealed, it's very likely to have been light struck by someone being curious over the years.
Several years ago I bought some 10x10 Kodak plates from a junk shop in Hollywood they had expired in the 40's. Lots of fog, but I was able to make a sort of decent positive from one of my negs.
You won't know until you try. As a guess, it's probably ortho, and you might try exposing for ISO 5 or so.

 

[Mike Wilde]

If the emulsion is no good, then you have great bases to start hand coating on!!! strip them with ammonia and start a fresh coating.

 

[htmlguru4242]

I might as well give them a try ... I'll throw an unexposed plate in the dev. and see what the base fog is like.

Mike - that really was my original intent when buying them, and I was going to ask what to strip them with. Ammonia, you say? Household stuff or stronger?

 

[Mike Wilde]

Household grade, and a moderate abrader - from my kitchen sink a nylon style scourer does it for me. Do wear rubber gloves. Slippery sharp edges as you rinse them, and the smell of the ammonia gets into your skin. Don't ask how I learned these points.