View Full Version : using unopened boxes of 100+ year old glass plates

6-Jan-2018, 11:45
Thought I had posted this at one time, but did a search in the FORUM and came up empty handed.

I have collected a couple of boxes of unopened 4x5 glass plates, probably dating back to around 1900. Now I want to try to expose and develop them. Have some 4x5 glass plate holders which have seen better times but hoping to make one or two of them useable once again.

Condition of the outside of one box to be "as new" but of course have no clue to how the box was stored.

Was wondering if anyone else out there has tried exposing and developing vintage glass plates. I assume an ASA of 4 or 6 as a starting point. But what developer to develop them in? Also would like to add some Potassium Bromide as a restrainer, but have yet to find a reference to the amount of Potassium Bromide solution to add to the developer or how much longer to increase the development time.


Pere Casals
6-Jan-2018, 13:08
Benzotriazole may work better as a restrainer.

Here you have some tips http://www.instructables.com/id/How-to-Develope-VERY-Old-Film-and-Get-Good-Results/

Low fog developer like HC-110 is recommended for those jobs. (see Step 7 of the link for a Bezotriazole dose suggestion)

If emulsion is delicate you may need to develop in cool water and extended times.

You can waste a plate, and use an stouffer wedge to calculate emulsion speed.

Once you have the actual emulsion speed it may be benefical overexposing and developing less, to overcome fog.

Check if it is ortho, in that case you also can develop by inspection in a tray with safe light.

6-Jan-2018, 13:08
Someone has recently posted in the image sharing section (http://www.largeformatphotography.info/forum/showthread.php?143513-Kodak-5x7-NOS-plate-age-75-Shot-today)...

6-Jan-2018, 13:54
What was the typical (or ideal) thickness of glass plates, or does it make no difference?

Pere Casals
6-Jan-2018, 14:18
What was the typical (or ideal) thickness of glass plates, or does it make no difference?

MF holders take 1/16" glass (1.5mm aprox), 5x7 and up holders normally always can take 2mm glass, some may take 2.5mm. Some 4x5 holders take 1/16" thin glass and some take glass like 5x7", this is 2mm or 2.5mm

So one has to measure what own holders take... I use 2mm glass.

As the format is larger a thicker glass is better. A 11x14" with 1.5mm glass looks very fragile and 2.5mm would be better.

6-Jan-2018, 14:21
Gold information, Pere. Thank you!

Pere Casals
6-Jan-2018, 14:31

I found the link to the source that time ago I saw: Denise



6-Jan-2018, 14:38
Thank you again, Pere!

Tin Can
6-Jan-2018, 15:12
I did it this week.

Look here.


6-Jan-2018, 15:27
Thanks you all very much for the info, especially the URLs. Looks like I will have too put off shooting the unexposed glass plates for a while till I purchase some 4x5 glass plate holders. Had a half dozen or so 4x5 glass plate holders, all in poor condition, for which I had hoped to piece together two or three useable ones. Carefully went through them just after I initially posted this thread, and discovered that they were in a lot worse condition than I thought. Fortunately they were given to me and cost me nothing.

Also will be using Benzotriazole instead of Potassium Bromide. Seems as though Potassium Bromide was the most widely used restrainer, but Benzotriazole "has the interesting properties of acting as anti-fogging agents without affecting in any ay other properties of he developer". Using Potassium Bromide as a restrainer and depending on the developer, one has to increase the development time up to 400%, just another variable that I will now not have to deal with.

Mark Sampson
6-Jan-2018, 17:28
If they're blue-sensitive or ortho plates you can develop by inspection under a red safelight. That's how it was done at the time. And if you plan to print them by a hand-made process, a la platinum, salted paper, etc., more contrast is better.