Digital BW, The Print

----- Original Message ----- 
From: "J Vee" <j.vee@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Tuesday, December 23, 2003 6:33 PM
Subject: [Digital BW] "Encapsulation"


>Is there evidence that gelatin "encapsulation" of the print is
not
consistent with extended longevity?  The reason I ask is that,
since I am
also a traditional "Carbon" printer, I wonder if there is
something to be
learned from those techniques which have resulted in well
preserved prints
from at least the late 1800's.  One feature is that receiving
paper (paper
to receive the transferred pigment image which is a suspension of
pigment in
gelatin) is floated (basically immersed) in a gelatin suspension.
After
receiving the image, this "sandwich" is made permanent by soaking
in
formalin solution.  I have left out a lot.  This, I believe,
cross links the
protein molecules of the gelatin.  These images are about as
permanent
(including the 3 & 4 color ones) that have been made.  As a
pathologist I
can attest to the preserving effect of formalin.  A word to the
wise -- it's
a possible carcinogen, but that concern has probably been
overblown.  Any
tests been done on digital prints?  Any thoughts?  J Vee<

The Carbon B&W print consisted of a carbon pigment + in your
description a hardened gelatine on a rag paper usually. The
inkjet prints made with carbon pigment inks are often not printed
on gelatine coated paper, the paper often isn't a rag paper. The
sizing of the paper may however contain gelatine or PVA. The
gelatine or PVA coated papers (swellable) are more compatible
with dye inks. Hardening that combination will then not be much
different from hardened analogue photographic prints. If the dye
and gelatine allow a waterbased process.

There may be a possibility to apply a gelatine coating on the
microporeus paper coatings usually used with pigment inks and
then hardening with formaline afterwards. The waterfastness is
less of a problem with pigment inks and microporeus coatings.
Risks could be a less flexible toplayer or one that gets less
flexible in time and possible yellowing in time of the hardened
layer. Gloss will be lowered by the hardening.

All the B&W films that I have developed in the 70's were treated
with a formaline hardening at the end of  process. That was a
good decision as I still can use them despite a not so archival
storage in time. If I remember it correctly the PH grade of teh
emulsion had to be correct before the formaline was used, wonder
whether that can be met in digital prints.

I have seen an article in a magazine mentioning the use of
waterglass as a sealing for prints that had to be used outdoors.
More to increase the waterfastness. Could be a way to seal matte
prints.

Ernst