Digital BW, The Print

Considering that the past successful "coating" experiments discussed
here also vastly improved the visual and, reportedly, measured d'max
on matt papers it seems obvious that embedding the pigments into a
clear coat does the same thing you are refering to with glossy papers.

As far as the ink itself goes it's not difficult at all to measure
their relative opacities and opacity "is" density by definition.

The more interesting question would be just how does the "Photo" ink
differ from the matt variety and is it absorbed into the coating on
glossy or is it just in a clear medium that remains when the ink is
dry? It has been reported that the Photo black d'max when used on matt
papers suffers drastically. Having such a clear medium absorbed away
into microporous papers could explain that loss.

Silver gelatine photo papers have precisely the same visual
characteristics glossy vs matt that you are talking about. There
doesn't need to be any difference in adsorbtion characteristics of the
actual pigment itself to get the same difference in look. The
reflection characteristics themselves can explain all of it. It isn't
it's absorbtion of light that makes it look darker, it's simply
because it "is" darker eg: the impinging light has been reflected away
and is not visible to the eye.

Having said all this doesn't answer your desire to measure the actual
adsorbtions of the two types of ink/papers without reflective
interference. If you ever manage to do it let us know the results.

Regards
Duane


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Steve Kale
<stevekale@b...> wrote:
> 
> When, under diffuse lighting, I look at a sheet of matte black ink
on matte
> paper next to a sheet of photo black ink on "photo" paper, the
latter simply
> looks more black - despite your "valleys and hills" argument.  As a
result,
> I conclude that the photo ink/paper combo is better at absorbing light
> (ignoring specular highlights for the moment - see below) and that the
> measured dMax difference we observe between matte and photo is
largely real
> despite the argument that the matte paper is likely to reflect a
little more
> light back to a 0/45 degree sensor because of its more diffuse
reflection.
> The issue with photo paper is that it is more prone to specular
reflection.
> This is a big DISadvantage.  I am sure that if photo only produced
the same
> black (visual or measured) as matte then matte would rule the day. 
I would
> argue that matte paper has been the choice du jour for inkjet only
because
> of issues such as "bronzing" and "differential gloss".  These have
largely
> been dealt with by the new K3 inks.  The next step is a paper with a
finish
> more closely resembling the air dried fibre print.  Personally I
like the
> finish of matte papers and if one could achieve a photo dMax on
matte then I
> would do all matte.   I suspect though that that day is still a wee
way off.
> Photo ink/paper just took a massive leap forward.  I don't see such
gains in
> matte ink/paper.