I have some glass plate negatives that were made by my grandfather. Some of the portraits have the background blocked out by some kind of coating. As the coating is damaged I would like to repair the negatives to preserve the original effect.Does anyone have an idea of what the coating may be & how could I repair it.The coating is a dark grey,matt,chalk like finish.

-- Melvin (bramley@nanaimo.ark.com), January 26, 2002

Answers

Best not to mess with it. And keep the neg's in a dark safe place. If you can, make some contact prints while the neg's are still useable. Duplicate the contact prints.

-- Les (1fatcat@usa.com), January 28, 2002.

You could easily make contact prints with them and then scan the prints, put into photoshop or similar editing program to repair the damage. That way you don't really have to do anything to your plates other than clean them before making your contact prints. I did this and it works very well.

-- shannon (shannon76@angelfire.com), January 28, 2002.

Melvin, are you sure these are glass negs you're talking about and not something else? An old glass neg wouldn't necessarily have backing on it....your description of a dark grey/chalky coating fits in with an ambrotype....it's hard to say without seeing the images, but my advice would be to try to contact a state or local archive, or historical society in your area...even a public library if they have a special collections room or genealogy wing. I work in a state history museum and we give conservation consultation on objects (furniture, textiles mostly) to the public, but with old photos, particularly glass plates & cased images, my advice would be to contact a conservator or an archivist at the least....if it is an ambrotype, or even a glass plate with flaking or chipped emuslion, there's very little that you can or -should- do....seek professional help. Feel free to contact me offline if you need any help, I'm not a photo conservator, but good luck either way....

-- DK Thompson (kthompson@moh.dcr.state.nc.us), January 29, 2002.

No one has mentioned the possibility of the gray stuff having been applied by the photographer for the purpose of retouching. The questioner did remark that the background was blocked.

Pat Gainer

-- Patrick A. Gainer (pgainer@rtol.net), February 09, 2002.