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karavelov
03-29-2007, 08:09 AM
Hello,
I have received some old ORWO 9x12 glass plates that seem not so badly damaged by the time. However I have a problem loading and processing them in the dark. How I tell which is the emulsion side of the plate in the dark? The glass plates do not have notches in the corner.

Thanks is advance for some tips
Luben

Ole
03-29-2007, 08:23 AM
When I bought some new glass plates a while ago (Slavich), I was informed that they were packed in pairs with emulsion facing in.

So the first plate has emulsion down, the second up, the third down, and so on.

What I don't know is if this has always been the way it was done...

karavelov
03-29-2007, 09:46 AM
Thanks Ole,
My plates are also packaged in pairs. I will check if this principle also applies to them and post my findings here

gordrob
03-29-2007, 10:09 AM
So the first plate has emulsion down, the second up, the third down, and so on.

What I don't know is if this has always been the way it was done...

I have some Kodak P300 and HP3 plates from the 1950s and both "are packed in pairs with the emulsion coated surfaces face to face."

It would seem that this has been the normal way of packing glass plates for a number of years, I would imagine it is that way so you know how to identify what is the emulsion side since there are no notches.

Regards
Gord

athanasius80
03-29-2007, 02:53 PM
Just hazarding a guess, but wouldn't the emulsion side have a different look than the glass side? The vintage glass plates I've seen in plateholders have a "yellow" side and then a plain glass side.

JPD
03-29-2007, 03:03 PM
...or creamy white on the emulsion side, and dark blue on the back. But it's difficult to see that in total darkness! :p

Ole
03-29-2007, 03:05 PM
They look different, but that doesn't help much when you're loading unexposed plates in the holders.

They feel a little different too - but it can be very difficult to tell the difference between emulsion side and anti-halation coating on the back side!

KenS
03-29-2007, 11:34 PM
How I tell which is the emulsion side of the plate in the dark? The glass plates do not have notches in the corner.

Thanks is advance for some tips
Luben

Luben,

Many moons ago when exposing sheets of graphic arts film that had been "cut down" from larger sheets I used to place a small piece of one corner to my slightly damp lower lip. The emulsion side will feel slightly "stickier" to the damp lip than the back of the sheet of glass will..... a trick that I was shown by my mentor when he was using 8x10 glass plates

Ken

Ole
03-30-2007, 12:50 AM
Ken, that trick works well - unless the plates have an anti-halation backing. Unfortunately most plates do. :(

Michael W
08-06-2007, 04:49 AM
The few packs of vintage plates that I've used have all been packed with the plates in pairs, emulsion side face to face as noted above. However I did also get a box of fairly modern Agfa 6.5 x 9 plates & they were packed differently. 10 in the box, top 9 are emulsion side down & the last one is emulsion side up. This was confirmed by an Agfa product sheet.

steven_e007
08-06-2007, 05:28 PM
Hi,

I've got quite a collection of boxes of plates. Kodak, Ilford, Gervart and a few others.
They are mostly just collectable curios as they are usually all fogged beyond being useable, but I have tried quite a few and sometrimes find the slower ones (things below 50 ISO) ok.

I once tried some 'Wellington' plates which I think must have been circa 1920 and they weren't too foggy at all. Very sharp and contrasty, too. But I reckon they were only about 1/2 ISO, which is probably why they didn't fog.

Many are packed in pairs, always emulsion side facing each other, but quite a few are packed in fours. Here the emulsion always faces in towards the centre, but you have to be careful not to get confused as you remove the plates from the packing in the dark. From my 1920s Wellington plates to some 1970s Ilford and the Kodak and Gervart, too, this seems to have been the rule for several countries for over 50 years. The Agfa plates mentioned higher up the thread are the only exception I've ever heard of...

I have looked at a few orthochromatic plates under red light and really can't tell the difference between front and back. I would guess the front is creamy white and the back of a 'backed' plate would probably be red, but under red light everything is red! If it is unbacked and orthochromatic or ordinary then it is obviously easy, as the glass back is shiny and the emulsion is matt.

For pan plates with the sticky finger test, it only works on unbacked plates or plates where the backing is behind the emulsion, rather than on the other side of the glass. I have used plates with the anti halation layer under the emulsion and a 'clean' glass back, but since my darkroom isn't completely 100% light proof I use a changing bag, so can't get to lick my fingers to try to tell the emulsion side by stickiness! I have been told you can tell the emulsion side by smell, too. I've certainly experienced this with some matt printing papers that seemed identical on both sides, but again another limitation of using a changing bag, I can't get my nose in there...

I reckon knowing how the plates are packed is the only reliable way...

Steve