QTR-Quadtone RIP

Got it. Thanks again, Paul.

--- In QuadtoneRIP@yahoogroups.com, Paul Roark <roark.paul@...> wrote:
>
> Both LC and LM are needed.  LC is way too green.  Sadly, there is simply no
> good "blue" that offsets the carbon warmth.
> 
> Paul
> 
> On Tue, Mar 26, 2013 at 4:49 PM, mccarvill <mccarvill@...> wrote:
> 
> > **
> >
> >
> > Thanks, Paul. Would the issue go away if only LC or LM were used, and not
> > both? In your paper you note that LC and LM are needed to offset the warmth
> > of the glossy carbon pigments. LC I understand, since it's cool. Why is LM
> > also needed?
> >
> > M
> >
> > --- In QuadtoneRIP@yahoogroups.com, Paul Roark <roark.paul@> wrote:
> > >
> > > Hi Mark,
> > >
> > >
> > > > In the PDF, you note that:
> > > >
> > > > `If the LM fades faster than the LC, the print will take on a green hue
> > > > that most viewers find rather unpleasant. How well matched the LM and
> > LC
> > > > color pigments are in terms of their rates of fading becomes a
> > significant
> > > > issue for image stability.'
> > > >
> > > > Seems like a big caveat. Is it possible to quantify or mitigate the
> > risk
> > > > here?
> > > >
> > > In terms of quantification, I'd assume the testing of the Piezo inks at
> > > http://www.aardenburg-imaging.com/ are about the same as what you'd see
> > > with MIS blended B&W inks. In my less stringent testing early in the
> > game,
> > > I found MIS and Piezo inks about equal. Most casual printers will
> > probably
> > > never notice the shifts. On the other hand, some of those test prints
> > > turned in a negative Lab A (greenish) after an exposure equal to 3 years
> > of
> > > commercial gallery light level. I would be hesitant to have my reputation
> > > depend on that type of performance.
> > >
> > > On the other hand, I will have show based on the Epson Noritsu (Claria)
> > > dyes that are clearly not in the 100% carbon league either. I'll have
> > lots
> > > of materials that make clear the distinction between the media, however.
> > >
> > > How to mitigate the color shift is not totally clear. You can see if
> > there
> > > are tests of prints with protective sprays that help. Oddly, sometimes a
> > > spray affects one color so much more than another that the color shift
> > > becomes worse.
> > >
> > > My answer for high end gallery quality work is to avoid third party color
> > > pigments.
> > >
> > > Note that for the color settling issue, I did not test whether agitation
> > of
> > > the wide format carts took care of the problem sufficiently. With Eboni
> > > the changes in the wide format tubes and dampers seems to be alleviated
> > by
> > > the motion of the head and tubes. I'm not sure that will be the case with
> > > the color separation.
> > >
> > > Overall, my last solution for glossy pigment prints was to go with MIS
> > > carbon in most channels and tone with Epson LM and LC. See
> > > http://www.paulroark.com/BW-Info/4000-5K-Plus-cmy.pdf
> > >
> > > Then again, I've all but abandoned pigment glossy printing. For high end
> > > work, I think matte under glass works better, and for pure high impact,
> > > dyes win.
> > >
> > > > I'd probably be using Canson Baryta Photographique, so presumably
> > > > a fair amount of LM and LC would be needed for a neutral print.
> > >
> > > Yes, carbon on glossy paper is very warm -- what I call "sepia" tone. It
> > > takes a lot of color to overcome that degree of warmth. If you look at
> > the
> > > Aardenburg testing, the Epson LC and LM seem to resist differential fade
> > > the best.
> > >
> > > Note that I think the HP Z3200 grays are the best neutral/cool inks. If I
> > > were designing a gray ink with that type of R&D available to me, I would
> > > not use the C and M that are in the color positions. The ideal color
> > toner
> > > in terms of color shifting is a single pigment that offsets the carbon
> > > warmth. That way the fade path is a straight line back to the carbon
> > > warmth. I've actually printed with such a color -- indanthrone blue. But
> > > it was not properly prepared for inkjets, and the third party B&W volume
> > is
> > > not sufficient to justify the cost of doing so. There are also issues of
> > > color constancy & metamerism that might affect toner pigment selection
> > and
> > > are much different than what one would want in the color positions. HP
> > and
> > > the other OEMs have the volume and expertise to do these things. It would
> > > surprise me if they are just using their color C and M pigments in their
> > > gray inks.
> > >
> > > Being stuck with existing third party color inks for toning when doing
> > the
> > > MIS designs, what I did was switch to the R800 blue instead of the
> > magenta.
> > > This narrows the angle between the color toners and helps to some degree,
> > > but not really enough for a huge impact on the problem.
> > >
> > > Sorry I don't have a great, 100% solution for you. With third party B&W,
> > > blended color + carbon inks I'd test whether agitation is sufficient to
> > > avoid the color drift from settling in wide format printers, and I'd
> > simply
> > > assume that they are not a top collectible or museum grade print. That
> > > said, they are fine form casual printers and should not show much change
> > in
> > > normal household lighting for a number of years.
> > >
> > > Paul
> > > www.PaulRoark.com
> > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >  
> >
> 
> 
> [Non-text portions of this message have been removed]
>