Re: Snaps

howard wrote:
> 
> Can't think of an appropriate Ng, so here goes...
> 
> How do I make a photographic image last a very long time ? I
> mean a *VERY* long time. I'm talking 5,000 - 20,000 years !
> 
> Not digitised but as a viewable image, or negative/slide/print.
> 
> Sealed in glass, in a vacuum ??  Laser burn, or etch the image
> granite or carbon? Or natures way, in amber. ?

Survival time as such is not the issue.  A frankfurter lasts 50+ years
in a landfill (dated by proximate newspapers).  Under what
conditions?  What optical resolution?  Photoetched nickel and such
will pretty much last forever short of corrosion and abrasion.  Ditto
photoetched glass and moisture.  Photoresist on a silcon wafer,
expose, and etch.  It's good forever short of fire, hydroxide, or
dropping it.

How long did the Rosetta Stone last?  Pictures on gravestones?  Do
offset or silkscreen of pigments or noble metal precursor onto
ceramic, fire, then glaze.  You can do ink jet printing of ceramic
cups and slabs now - that gives you hi-res color.  While it is
invulnerable, you need considerable infrastructure.

Make a B&W photo and cast inside a thck slab of polyester resin or
PMMA.  Good for thousands of years.  Platinum tone it and cast in
plastic is better. Add 0.1% Tinuvin 327 (pale yellow) or Tinuvin 328
(colorless)to the resin for UV resistance, but keep it out of sunlight
anyway to avoid degrading the resin.

If all you want is a time capsule, B&W photo (preferably platinum
toned; well-washed with distilled water) loosely rolled, inserted, and
pumped own hard in a heavy wall Pyrex vacuum tube or ampoule to remove
10% moisture in the paper, then properly flamed shut with a bishop's
miter seal.  That should last the age of the universe if you keep it
out of sunlight - so give it wrap of several layers of aluminum foil
or electrolessly plate nickel.  If you are really paranoid, put the
sealed ampoule in an inch-thick wall Alloy C-2000 Ni-Cr-Mo (Haynes)
screw top high pressure bomb (with internal padding).  

-- 
Uncle Al
http://www.mazepath.com/uncleal/
 (Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?"  The Net!