Eastman Dry Plates: what speed can I expect?

[shalom_septimus]

<p>I'm not even sure I'm posting this in the right forum... it equally could belong in Classic Manual, Alternative, or Large Format, but here goes:</p>

<p>I recently scored a factory-sealed box of 4x5 Eastman Dry Plates, and a holder for same to fit my Speed Graphic. I thought it would be fun to go out and shoot some of these, but I have no idea how to expose them. The box doesn't give me any guidelines, other than stating that the red seal means that it's Extra Rapid. Diligent googling hasn't turned up any info as to what speed these were even when new, let alone 100 years later: the box has no process-by date, but the seller said there were other items stored with that which were dated 1908. I don't even know what the range is: are we talking ASA 1, ASA 25, or somewhere in between? Even slower/faster? Also, are they blue-sensitive or orthochromatic? It doesn't say that either. (I'll worry about developing them once I have them exposed...)</p>

<p>Of course the next question is, how do you know which side has the emulsion. I haven't opened the box yet, so I don't know if there's a notch. Someone writing to the editor of Photo-Era magazine back in 1919 (found on google books) recommended biting it gently and see which side sticks to your teeth. I think I'll not do it that way, thanks.</p>

<p>So why am I doing this? Why not, it's fun, and I wanted to try it out. If it comes out a usable negative or two, that's a bonus. Didn't even cost me all that much. (You can still get current production 4x5 glass plates, but they cost stupid money -- current pricing is 237 euros for a box of 25, plus shipping -- so I'm not likely to be using those...)</p>

<p>Thanks in advance.<br>

Shalom</p><div></div>

[john_shriver]

<p>They are wrapped in paper in pairs, with the emulsion sides facing each other. Also, the emulsion side has a distinct feel, not like glass.<br>

They are orthochromatic, so you can load them by red safelight. The Panchromatic plates from Kodak were Wratten and Wainright brand.<br>

Try not to get glass slivers in your hands.<br>

I'd take a wild swag at EI 10. Maybe EI 25. How about shoot one at each speed, and develop by inspection in D-76?<br>

There may be an instruction sheet in the box with processing times or exposure times. They would be printed to match the characteristics of the batch.<br>

I shot a few plates from a box of Wratten & Wainright of similar image, the entire outer half of the emulsion was totally fogged by oxidation or some other atmospheric process. Only the center had remained gas-tight. Unfortunately, they are not in a vapor-tight package.</p>

<p> </p>

[paul_miller10]

<p>Shoot your first plate as if you were making a test strip for film. Make several exposures on one plate by pulling the dark slide out of the holder a half-inch or so and noting your exposures.</p>

[jpo3136b]

<p>I'd consider hanging onto a few of these and leaving them unused, just for posterity. You can always come up with a way to coat your own, if you really get into it. </p>

[bob_himmelright]

<p>I bet they're completely fogged at this point....80-90 years is a long time.</p>