PDA

View Full Version : Info on dry plates please



Schlapp
04-07-2006, 08:00 AM
I have an assortment of unexposed dry plates and would welcome some info on them please - such as what to rate them as.
Kodak Ortho Rapid
Eisenberger Reform Platten
Imperial Eclipse

The last one has some developer recipes on the box;
"MQ formula"
Metol
Hydrokinone
Sod. Sulphite
Sod. Carbonate
Potassium Bromide
+ water
develop for 4 mins !

Anyone know of a current eqiv. ?
Another one for "Pyro-Soda"

Donald Qualls
04-07-2006, 10:38 AM
The "MQ Formula" that you have there is the same ingredients as Dektol. You could find the D-72 formula (try DigitalTruth's technical information page) and compare the two, and likely find your Dektol will do that job. That time is very close to what my 1950s vintage packets of Kodak MQ Universal developer call out for plates.

Pyro-Soda was a common developer in the pre-D-76 era, though it fell out of favor due to grain when smaller formats made solvent developers like D-76 more preferred; it's the simplest pyro formula, and should give similar results to ABC Pyro (aka Kodak D-1) or PMK.

All the others will likely share the same process time; B&W films and plates were made to use the same process times across brands and types for decades before color stole the market and relegated B&W to "art" photography.

For speeds. Hmm.

Kodak Ortho Rapid is probably ISO 50 equivalent, though it might be one stop faster (but no telling how much speed it's lost in the 50-80 years since it was made). For the others, you're on your own. Maybe you can do a test strip by withdrawing the dark slide a bit at a time and making multiple exposures (to avoid burning all your plates with bracketing or text exposures)?

Schlapp
04-10-2006, 04:29 AM
Ok, first go with the Imperial plates; rated at 3 developed 4m 15secs in Rodinal and the image is great - although the emulsion is rather fragile :-)

.. and the image, slightly cropped is here http://www.photo.net/bboard/uploaded-file?bboard_upload_id=29341684

Donald Qualls
04-12-2006, 09:43 PM
Nice! I see you have the obligatory light leak in the plate holder (I've got fifteen holders for my Ideal, and I think 8 or 9 of them leak under at least some conditions -- eventually I'll figure out *which* 8 or 9). Other than that, it looks pretty good! Rated at 3; that implies it's lost at least two stops, probably more like three or four (original ASA 12 or 25, x2 for the 1960 change in testing method to give 25 or 50), which isn't far out of line for an emulsion that's at least fifty, and possibly up to 80 years old.

You'd most likely pick up half a stop to a full stop in Dektol compared to Rodinal, if that matters to you...