Uncurling old negatives?

[kiwicol]

I have about 150+ old negatives from the USA from the late 1800's but they are all curled/rolled up, some single others with 3-4 together. If I am careful I can gently unroll them and scan them, but have had to develop a system to hold them flat while I do that. Does anyone have any ideas how or even if, these can be flattened out again after all this time? They are very difficult to store, and I believe they are also nitrate negatives.
Very historic negatives from the North West USA and from shadows in several appear to have been taken by a lady photographer.
Any ideas suggestions would be appreciated

[Doug Nelson]

Here's Kodak's recommendation:

"Film curl is due to humidity contraction of the film when stored in a
wound configuration at a relative humidity of less than 40%. This is
most often a temporary or reversible change, and can be correct by
rehumidification of the film. Allow the film emulsion to reabsorb
moisture while in an atmosphere of higher relative humidity. Use of a
humidifier in a closed room will accomplish this, but be sure that the
mist does not get directed onto the film itself. The film will unroll
to an extent with rehumidification. Once this has occurred*, you may
then place the film into an archival storage envelop or sleeve, place
beneath a weight, and then bring the atmosphere closer to 40-50%
relative humidity to retain its dimensional flatness.

*be sure that the film is not moist to the touch."

[Mike]

If they indeed are nitrate based there are several safety considerations to be kept in mind. Here is a good start:

http://cool.conservation-us.org/byau...r/negrmcc.html

Also do a Google search. Note that some say a true nitrate based negative can burst into spontaneous combustion at a temperature as low as 103 degrees F. Most of these articles relate to movie film, but as I understand it they also made nitrate sheet film and the same problems can occur with them.

Be cautious!

[kiwicol]

Thanks for that info. I'm not certain how I can follow Kodaks recommendations but will try and figure out a way. They look like they have been curled for their entire life (114 years!) so I might not have any luck. At least scanning them will preserve a copy.
I am not 100% certain they are nitrate but tried a burn test on one blank negative and compared that with modern safety film, it burnt very fast with a bright yellow flame, so I think they could well be, so I am taking extra storage care etc.

[Mike]

A couple of thoughts:

Do you have a museum or university in your area that may have some expertise on this?

While doing something similar with curled negatives, I found getting about 10 hands all on the negative, holding it down on a sheet of good glass while we worked another sheet of the good glass above it then taping the two sheets together so it would not curl back up, seemed to work. We then copied it using a camera.

[kiwicol]

Not certain about that will have to phone a few and find out.

I have been through what you mention and that is how I started scanning them, the ones by themselves are problem enough but when you get 3,4 or more rolled together in about a ¼ inch circle they are fun, especially the middle one. No way it wants to lay flat, no matter how many hands help!! Some of them are very brittle as well and are near impossible to uncurl without disintegrating as soon as you touch them. But its an experience.
If anyone wants to look at some of them check out the USA 1890's collection set on http://www.flickr.com/photos/pfam09/