Digital BW, The Print

----- Original Message -----
From: "Mr_Misty_44" <jharvey@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, September 20, 2002 11:17 PM
Subject: [Digital BW] Photogravure and InkJet


>
>
> I guess I'l simplify the question. What would make a simple etching,
> say drypoint, More archival than an InkJet print using the "Archival
> Carbon Pigment" inks and Archival paper. Is it the ink we use, the
> solvent , the paper we use or the coating.What is the weak link here
> or do simple etchings or Lithos suffer from the same archival
> problems. I don't see people screaming about the archival qualities
> of a Picasso print be it an etching or litho.
>
>                            John H

John,

Ernst summed it up pretty well in his earlier post which I have copied
below. Simply put the carbon particles in the inks used for etchings are
heavily encapsulated and protected from oxidation. The ink is the big
difference.

Martin

----- 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


(snip)

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