Posted by Arnold (192.231.106.2) on October 06, 2004 at 23:19:25:
In Reply to: Toning:- resending the link (Arnold) posted by Peter Gallagher on October 05, 2004 at 23:07:17:
Peter,
Thanks for persisting on this. The cleaning information is quite interesting for its detail. It's clear that cleaning involves complex chemistry about which we know very little. Even the "experts" are taking chances since long term effects of cleaning are unknown.
Another consideration is the likely improvements in the technology of reproduction. At some point, these prints will decompose beyond redemption and the only way to preserve a record will be through reproduction. It seems likely to me that colors, even faded colors could be identified by modern and future analytical chemistry - perhaps quite rapidly. Faded prints might be easily reproduced in original colors at some point. Treating prints with chemicals likely destroys color signatures. For example, oxidants might destroy chemical signatures that could be identified by mass spectrometry which could make faithful reproduction impossible.
Arnold