Found glass plate neg

[jwarren116]

So, I wanted to do some dry plate (maybe wet plate) work. I have a 5x7 and an 8x10 with a reducing back (in addition to the 4x5). Figured I'd track down some 5x7 plate holders on eBay. After some careful watching, I got 3 plate holders (1 needs some glue work) for $35. I was pretty excited to do some stuff with plates. Long story short, I open the box and unwrap them. I checked the two working condition holders and they're perfect condition. But I cannot figure out how the plates are secured into the holder. There's no moving parts (that I see) to hold anything in. There's no flap that comes down or anything. Seems like they'd just fall out when you pulled the dark slide out. Any ideas?

Okay, now the bonus... I opened the busted holder to find... an old glass plate! It was already exposed and developed, it appears. It has an image of two gentlemen dressed in funny clothes standing in a forest. The emulsion side of the plate looks like a silvery coating, but you can see through the non-emulsion side if you hold it up to the light or on a lightbox. Needless to say, I'm excited by my find. I'll make a print of it and post it. But how can I identify what kind of negative it is? I'm fairly new to the glass plate stuff. In the past I've just used liquid emulsions and some other concoctions to coat glass. They've never looked quite like this!

Thanks!

James

[Glenn Thoreson]

Plate holders load differently than film holders. Insert the plate in the bottom groove, press the plate down toward the bottom and it should pop in at the top. There's a spring in the bottom groove that holds it in place. To unload, slide the plate down and hold it there. Turn the holder over. It should drop out at the top. Don't let it fall out on the floor. As far as identifying you find, there's no way that I know of to identify the maker of plates unless they're still in their original package.