Photo restoration - how to deal with silvery sheen in parts of image?

[George]

Some 80 year old photos in my possession have an odd haze or sheen
over some areas, mostly within a couple centimeters of the edge. The
areas mostly affected are dark. Thus the shadow detail is obscured.
The haze or sheen is not uniform, but more evident in some dark areas
than other dark areas. It seems that areas sullied by fingerprints are
less affected.

The photos don't scan very well. The sheen is quite pronounced.

The angle of light has an effect on the sheen, but I can't find an
angle that gets rid of it satisfactorily to give me a good
reproduction (by digital camera).

Any suggestions?

G.

[Brian]

Hi George,

do you have an example you can upload to your web space and let us view?

[Mike Russell]

The silver sheen is a common occurrence in old photographs, and results from
the migration of free silver radicals within the emulsion. Some of the
radicals make their way to the surface, regain their electron, and deposit
themselves on the surface as metallic silver.

The silver may be physically removed by rubbing gently with a cloth. You
may also use commercial silver polish, but this is considered a high risk
procedure, and IMHO is unacceptable treatment for an irreplaceable
photograph.
http://www.colinrobinson.com/restore.html

Carefully photograph the image with a digital camera, and isolate the
brighter silver areas with a mask, and darken them separately.

Alt.binaries is not accessible to most people. Post an example on a web
page somewhere, or email it to Mike AT curvemeister.com and I'll take a
crack at it. I would request your permission to add this to my web site as
a tutorial.

[Robert D Feinman]

Photos with surface problems don't scan well. You need to copy the
picture with a camera using the standard lighting setup. This is
two lights at about 45 degrees to the surface so there are no
visible reflections. In really bad cases you need to put polarizers
over the lights and a polarizer over the camera lens to eliminate
the reflections.
A search on copying or a visit to a library or book store will show
you all the details.
If you don't have too many, a professional service can do this for
you.

[tacit]

Common problem with old silver-gelatin prints, especially if they were
not fixed properly when they were made.

It's unlikely you will be able to scan the print and get a decent
result. The "sheen" you describe is actually elemental silver forming on
the surface of the print, and it's reflective enough that you'll get
poor (and sometimes bizarre) results when you try to scan it.

In the prepress industry, the typical way of dealing with prints like
this is to put them in a special "copy stand" with lights around its
edge that illuminate the photograph uniformly, and then photograph the
print with a horizontal camera. By carefully controlling the lighting,
you can reduce the "sheen" considerably; you then make a print from the
photograph of the original, and scan that duplicate.

Many print shops and trade shops have the equipment to do this. If the
photograph is important and irreplaceable, I would suggest looking for a
trade shop or service bureau in your area and having them make a
duplicate print for you. (Some custom photo houses can do this as well.)
The duplicate will have more shadow detail, and will be easier to scan.

I've been told that you can sometimes remove this "sheen" by immersing
the print in photographic fixer, which works by dissolving the unexposed
silver ions in the emulsion. I have never attempted this and do not know
if it works.