Digital BW, The Print

----- Original Message -----
From: "Mr_Misty_44" <jharvey@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, September 20, 2002 6:08 PM
Subject: [Digital BW] Photogravure and InkJet


>
> In November 2001 there was a show of Photogravures at the Minneapolis
> Institute of Art. Alfred Stieglitz, Paul Strand, Alvin Langdon
> Coburn,Edward S. Curtis, and Lee Friedlander were among the
> photographers represented in this show. Can anyone explain to me what
> in the process of Quad B&W printing using MIS Carbon inks would make
> the print less archival than a Photogravure. Is the weak link in the
> coatings, Ink, Solvent...What. Or is there no differance.

Photogravure uses inks with an oil medium and bigger pigments particles. The
oil (linseed, alkyde) will harden on oxidation and that results in a strong
resin. That is in art printing on good quality papers,
no coating at all on the paper in any intanglio process.
In commercial photogravure on rotating presses (rotogravure) the ink is an
alcohol based varnish for faster printing with cheaper colorants. The paper
is bad as well. Nation wide magazines were printed that way till the 1970's
when offset replaced rotogravure.
Photogravure has long been considered the best printing process for
photography reproduction.

The weak link is in the inkjet ink medium mainly, very little medium, lots
of water, alcohol, glycol based solvent. The last disappears and the pigment
doesn't have a strong bond with the paper, the pigment particles are not
embedded in the varnish either. Epson pigment inks have an acryl
encapsulation of the pigment particles (Ultrachrome matte black is the
exception) that helps to protect the pigment, it gives a better bond and
makes gloss  printing possible.

All the processes to get a better protection of the inkjet pigment layer
like laminating or varnish coatings are done to get that same bond and
encapsulation of the conventional printing processes. A nice example for
outdoor prints is the First foil. Pigment ink is printed on that foil and
after printing the foil is heated in a tunneloven. The coating is made of a
resin with an reasonable low melting point (150 C.) the pigment sinks in the
caoting and the coating hardens when it gets cool again. Ilford had
something similar in the pipeline but it hasn't been released yet.

Ernst