Hi all,
If the photo dates from 1900-ish then it's more than likely a silver gelatine emulsion.
For any photograph I would recommend against solvent (wet) treatments by anyone other than a qualified conservator. The reason for this is that you can never be sure, particularly with older photos, what the emulsion is, or what deterioration is going on that you may not be able to see. More damage can be done to the photograph and is irreversible. Best leave this kind of treatment to the experts. Silver gelatine emulsion is sensitive to water in particular. Collodion emulsions react badly to acetone...there are a multitude of other problems.
Sherwood, I would suggest that to clean your photo you use dry methods only. The simplest and safest way to do this is using cotton wool, and grated crumbs of white plastic eraser (like the Mars Staedtler ones, just grated up with a [clean!] kitchen grater). I must stress that you shouldn't use this method if there are cracks or peeling bits on the surface of your photo, as they may get bigger and eraser can get lodged underneath the lifting bits.
So, if you have a nice healthy photo surface, get together enough eraser crumbs to fill maybe a teacup, some pure cotton wool, and a piece of clean paper. Make sure your hands are very clean, no creams or anything, and wear white cotton gloves if you have access to them (you can get them at the chemist).
The clean paper is for you to place over the bits of the photograph that you are not currently cleaning, to protect it from your hands - the warmth of your hands can soften the emulsion.
Take a small piece of cotton wool, or a cotton ball, and pulling it tight (so that it's not "fluffy") gently wipe it over the surface of the photo in a circular motion. End the circle by wiping over and off the edge of the photo - this means any loose dirt particles are swept off onto the work surface. Keep doing this across the whole photo surface, changing the cotton wool as it picks up the dirt.
ONce you have finished this process, if dirt is still evident, do the same thing with a bit of teh eraser crumbs. Put a spoonful of crumbs onto a corner of the photo, and with your fingers flat on top of the crumbs, gently move them in a circular motion across the photo, without applying any pressure. As the crumbs pick up dirt and turn a grey colour, tip them off and add new crumbs. Continue until you've done the whole picture.
If you have persistent small areas of dirt, you can cut a little chip or wedge off the eraser, and use the thin edge of the wedge to wipe over the offending area. Don't apply pressure.
If your photo is still too dirty to scan, or you're otherwise not happy with the result, it is probably time to call a conservator and get them to clean it up for you.
With the wax, you can try heating it up using the low setting of a hair dryer, protecting the rest of the photo with a mask of paper or card. As the wax softens, try to very gently peel/wipe it off perhaps with a cotton bud or a very fine, blunt knife. If it doesn't soften though, leave it where it is, because it's probably soaked through the emulsion to the paper base, and will peel away the whole thing if you try to force it.
I hope that helps
Prue
(Photo Conservator)
