Digital BW, The Print

>Paul wrote:

>> Many like the Gen4 K with a standard quad.  However,
>>the 25% dye does cause more fading and warm shifting.
>>That dye in the midtones would cause them to
>>fade even worse.  For the midtones, use a black
>>pigment that has no dye in the mix. <

Ernst wrote:

>What is worse then: a fading of all the greys proportionally
>or having a black that will fade more than the greys?

I'm not sure.

I think that the warming of the Gen4 in the black position, however, may be
hidden better in the shadows than if it were in the midtones.

Also, the general consensus is that fading of inks gets worse as they are
diluted.  I think this affects dyes more than pigments.  With a dye the
crystal structure becomes increasingly thin, which makes for more surface
area per volume, increasing the oxidation surface.  At least with pigments
the particle size remains the same as the ink is diluted.  Although even
here, I think that more of a lighter pigment would be better than a lesser
amount of the blackest pigment.

I'm curious how Epson is making its UltraChrome light black.  I'm sure they
won't tell me.  So, I'm going to fade test it against
diluted/matched-density UC Photo Black and Epson Archival black.  I may make
a quad based on the mix that does the best.  It seems to me such a quad
would not only be the toughest one possible, but it would also have the
potential for printing on glossy papers, depending on the black used.

Actually, such a quad may not be much different than the 7600 B&W printing.
I assume the reason the UC B&W images do so well is that the color is
withheld as much as possible.  So, what we have is the UC K & Lt. K, with
toning as needed, and a bit of light color pigs in the highlights, where I
understand the Light Black is too dark to use without visible dots.  Here,
it may even be that the light color pigs are more fade resistant than a
dilute (sparsely distributed) black particle.

So, the real questions as to how good the 7600 is for B&W may be, first, how
the light black does against the diluted Archival K in fade tests, and,
second, whether the 7600 really is stable enough to hold it's tones.  That
relatively high-gamut ink used as the B&W toner is going to have to be very
accurately controlled to avoid changes with time, temperature, etc. I'll
fade test the inks, but user experience will have to answer the other
question.

>It has been mentioned here before in parts but it would be nice
>to see a summary of the mixing ratios  (ratia?) for different
>quad sets and the resp. density values for a given paper. Would
>that be possible ?

I have generally published the ratios for the inks I mix.  They are in the
archives and the Files section.

If I mix a UC/Archival quad, I'll publish that also unless an interested ink
supplier sponsors the project -- which I doubt.

Paul
http://www.PaulRoark.com