Safe techniques for cleaning old glass negs?

[NortheastPhotographic]

I have acquired a number of old glass negatives. I would like to clean them prior to scanning, so I'm wondering if anyone knows a safe technique for doing so, that will not harm the emulsion or image... Any ideas?

 

[Nodda Duma]

I would just clean the glass side (windex) and leave the emulsion side alone.

 

[alanrockwood]

I have acquired a number of old glass negatives. I would like to clean them prior to scanning, so I'm wondering if anyone knows a safe technique for doing so, that will not harm the emulsion or image... Any ideas?

I am also very interested in answers to this topic. I have been scanning some old glass stereo slides (both negatives and positives) as well as non-stereo glass slides, and I would like to be able to do a better job. These images are about 90 years old, plus and minus a few years old. They come from my wife's side of the family.

 

[railwayman3]

I would just clean the glass side (windex) and leave the emulsion side alone.

I would agree with that. Some years ago our local Photographic Club was given a number of glass plates of local historic interest and we confined the cleaning to the glass side (other then a gentle dust with a soft blower brush on the emulsion where needed); The plates were passed on to the Local History archives, and I understand they were later scanned, and spots and flaws photoshopped away.

 

[RauschenOderKorn]

I´ve had the same problem, just for printing, not scanning.

My plates are 50-100 years old and I have used a plain soft brush to remove lots of dust. The glass side can be cleaned with alcohol or something similar. Furthermore some of the plates were stuck together, I put these in water overnight to be able to seperate them. Actually they had a clearer surface than the ones cleaned with a brush only, but I am afraid of the the emulsion seperating from some of the plates if I wet them all.

 

[Ian C]

The emulsion side of films or plates can be cleaned with naphtha using a small swatch of freshly-laundered (no fabric softener) soft cotton cloth or a tuft of cotton. The dampened cloth or tuft should touch the emulsion very lightly. Keep the action gentle and discard the cloth should it fall to the floor and use a fresh piece. It must be clean so that no particles (that might scratch the emulsion) are present. Then a squeeze-bulb blower can be used to puff off any small particles left from the cleaning pad.

Naphtha is anhydrous, so it won’t soften the emulsion, but will dissolve oily or waxy deposits. It can also dissolve such deposits from the base side without damage. Water-based cleaners, such as Windex can’t remove such deposits without considerable friction, which we must avoid on the emulsion side.

Test a corner to verify that this does no harm before proceeding. I have done this with films and prints for years. I have also used this on glass-plate negatives from the 1880s – 1915 or so. I’ve never observed any ill effects to my films, plates, or prints that I’ve cleaned with naphtha.

Naphtha won’t dissolve deposits of some water-soluble materials. It will remove greasy fingerprints, lipstick, grease pencil, and other such debris. When films are handled with sweaty hands, the water component can soften the emulsion and leave the 3-dimensional impression of fingerprints permanently embossed into the surface of the emulsion. These cannot be helped by cleaning.

The easiest-to-use, readily-available appropriate solvent is cigarette-lighter fluid, such as Ronsonal or Zippo. It’s naphtha. I’ve used this for film and print cleaning since 1989 or so.

If the emulsion shows any cracking or flaking in some areas, it’s best to leave those areas alone. Otherwise, the cleaning cloth or cotton tuft might catch the edge of damaged emulsion, lift the edge and make it worse.

I don’t recommend alcohol, since it usually contains at least some water, and that might soften the emulsion during the cleaning process. I have seen alcohol cause considerable curling of some film types, causing it to roll into a tube.

 

[Doremus Scudder]

I've worked with glass plates in the past. The ones I have cleaned up with a water soak, but they were in pretty good shape to begin with. One caveat: many older plates were routinely retouched using graphite (i.e., pencil). This retouching will come off with water and/or wiping. If you want to retain the total original image, retouching and all, it would be best to confine cleaning of the emulsion side to a light brushing or spot cleaning with a cotton swab or the like.

Best,

Doremus

 

[mark]

PEC 12 is amazing stuff.

 

[alanrockwood]

PEC 12 is amazing stuff.

Can you tell us more about PEC 12? It looks like it is pretty expensive. Is it better than something like Ronsonal lighter fluid?

 

[mark]

I worked for a short time in a special collections darkroom, printing very old negs, many were glass plates. I am not a conservator but the folks I worked under were. Some of these were very dirty with years of grime, the negs not the conservators. One even came in with gum, some with tree sap and the only thing I was allowed to use was PEC 12. It cleaned everything I threw it at.

I have a feeling my boss would have crapped out several cows if I went after one of her babies with lighter fluid.