Digital BW, The Print

The way I see it, it's not just about the amount of pigments. It's also
about how they are applied when making the print. The "joy" of a fixed
color ink set is that each dot on the print is the same color. If there
is fading, even differential fading, it occurs evenly across the print.

When you print with color inks (Ultrachromes, or variable tone inks) you
are putting dots on the print which are different colors. If there is
differential fading, you can more easily get a color shift, or a color
cast across the print.

Does this mean anything in practice? It's your money - you get to
choose.



On Wed, 2004-04-21 at 08:38, ccolbertbw wrote:

> I find it hard to believe that "mixing" the colors in the bottle requires so much less color 
> pigment than separately applied dots that it has a differential effect on longevity. Perhaps 
> it is an issue at the extreme (e.g., very cold where lots of blue is applied), but I would 
> guess that an equivalent cold ink wouldn't have all that much less color pigment. 
> 
> 
> Costa Colbert
> 
> > In a recent phone conversation with Bob at MIS he expressed his own
> > doubts about the RIP approach, echoing my own concerns.  The
> > implication (as I interpreted his remarks) was that the amount of
> > color pigments (which he said are made of "various polyesters") used
> > in the RIP technique is greater than the tiny amounts mixed into the
> > carbon inks of gray scale sets (I don't know if anyone has actually
> > calculated the difference).  He said that the mixed in amounts are not
> > significant enough to affect the "carbon status" of the inks.  Paul
> > Roark recently expressed similar concerns (see msg #43963, 4/16/04).
> >
> > 
> > My own tests give me doubts about pigments.  I have a Septone print
> > (multi-tone gray scale inks) on my windowsill that began showing signs
> > of fading at 125 days.  Right beside it is an Eboni BO print (both on
> > PhotoRag) that is over 150 days now with no signs of fading.   Of
> > course that's an unfair torture test (bright daylight and a small
> > amount of direct sunlight every day), but it nevertheless shows a
> > difference in the inks.  I plan to do a windowsill test on a UT7 print
> > when it's available.
> >


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