Plate thickness

RobertP

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I'm in the process of converting a 12x20 plate holder for wet plate use. The glass I'm using is framers glass for the plates. It will fit into the holder easily but there is some play between the plate and the end flap that holds the plate down against the septum. Does anyone know what the thickness of the dry plates were/are? Thanks, Robert
 

Jim Noel

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Most people I know use 1/8" glass. Is there a spring behind the glass to help push i against the edges of the holder?
 

dwross

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Robert,

I've been collecting old dry plate negatives to build as complete a picture as possible for my own work. If you place an old plate alongside framers' glass, the old plate is a bit thinner (about the thickness of thick watercolor paper.) Since cheap, easy-to-salvage picture frame glass works just fine in my old plate holders, I haven't reached for that extra measure of 'authenticity'. Long story, short(er), I'd guess that the little bit of play in your holders is normal and OK.

d
 
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RobertP

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dwross, I was guessing the same thing. This old plate holder has two triangular little metal points down near the end flap. I imagine that was to make it easier to get the plate out. They are almost flat against the septum and are pointing inward (naturally) There were at one time the same kind of points near the top just in front of where the glass sides up under the lip.(darkslide handle end) The marks are still there where the points have worked their way out. So I guess they figured their plane of focus was great enough that the extra .010- .015 of play would not effect their image. Has anyone else seen these type of points in an old dry plate holder? This is an old 12x20 F&S 1903 dry plate holder.
 

doughowk

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My Korona 7X17 dry plate holder has a small metal swivel on one end; but in the same area it appears to be missing something like you describe. Could you include a photo?
 
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RobertP

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Doug, I'll send a photo sometime tomorrow I pulled them out and just covered the entire inside with polyurethane to protect the holder from the silver nitrate. I'll replace them after it dries. They are made from a thin sheetmetal material, diamond shaped, about 5/8" long and 3/8" wide in the middle of the diamond. They just press one end into the wood rail and leave the other half sticking out to act as a rest for the plate. I've seen these at the local hardware but I'm not sure of the proper name. They go in much like framing points... same concept. Robert
 

PHOTOTONE

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If these "points" press on the emulsion side of a wet-plate they will contaminate the emulsion/collodion. Only silver or plexiglass should actually touch the collodion side. Many people modify a sheet film holder by cutting out the middle septum and gluing plexiglass corners in to hold the plate.
 
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