On Sun, 22 Jul 2018, Warner Losh via cctalk wrote:
Somewhat of a tangent, but this just popped up for me.
https://www.theatlantic.com/technology/archive/2018/07/microfilm-lasts-half-a-millennium/565643/
and I thought of this thread. Apologies if it's a duplicate..
Iff deliberately processed for archival permanence, metallic silver is
long lasting.
But, there have always been a lot of shortcuts taken to save time or
money.
A LOT of photographic materials were not adequately fixed ("hypo"/Sodium
Thiosulfate?), and/or not adequately washed and or neutralizing the fixer.
Archivala permanence calls for a fixer neutralizer, not just washing.
For example, the Polaroid 55-P/N (4x5 print plus negative) had a different
exposure index for the negative and the print, so one or the other would
be off on exposure. The negative desperately needed to be more
thoroughly fixed and washed, or it didn't last at all.
Similarly with "stabilization" black and white prints. (anybody want an
extra large stabilization processor? home lab movie film processing
equipment?)
There were many variations in the paper itself for photo prints. Some
lasted better than others. Kodak has discontinued manufacturing of B&W
photo paper, but there are a few other manufacturers still around.
Color was done with dies, rather than metallic silver, and those fade.
Remember how OVERLY bright Kodachrome was? Ektachrome held up a bit
better.
Longevity of digital data is predicated on periodic re-copying, and
periodic transfer to other and newer media.
"Cloud" is tempting, but the internet is written in sand; do you know ehre
your data is?
--
Grumpy Ol' Fred ci...@xenosoft.com
