QTR-Quadtone RIP

Ernst,

> ...
> An RC paper that I like to use with my HP Z3xxx printers, the Epson
> Proofing White Semimatt, shows some bronzing.

Epson Semimatte was what I settled on and bought a roll of the last
time I was doing wide format neutral glossy printing.  The Red River
UltraPro Satin may be similar, though brightened.

I was spraying the prints at that time.  I want to do away with spray,
however.  I'm not sure how the HP with glop will scale and print in
wide format yet.  The 7800 is next up for a "Dual Quad" setup that
will have the HP + Glop along with Eboni-4.

I think the bronzing is fairly typical of pigments -- particularly
coated pigments -- on glossy paper.  The last time I used MIS pigments
on glossy paper, they were not free of the artifact either.  So far,
this HP + glop combo, at least in the 1100 and with the papers I've
used, seems to be the most free of the bronzing artifact that I've
seen. (Dyes, of course, still have a huge edge in some respects.)
Right now, I'd probably select Canson Baryta with HP + glop midtones
(not 100%  sure of  the PK yet) as the top contender for  my 7800.

> ... The HP ID Premium RC papers show it less in my experience.

I suspect the companies  are pouring money into a way to solve the problem.

> Would an
> overprint with MIS glop have another effect or is the bronzing set in
> the ink medium and no extra layer of glop will cure that ? Opinions
> differ on what varnishes etc do to bronzing.

I think the use of a gloss optimizer at the time of printing can have
some effect, and a subsequent over-coating can help further.  I was
going that route for  a time but found too many negatives.  The sprays
do a better job and the solvent based ones dry with a harder coating.
I don't  want either step in my workflow.


> I am also using the CMYK HP Vivera inks in a HP K5400DN Officejet and
> consider a B&W version of an A3+ Officejet model as a next step...

> ...The thermal heads ... MIS glop may not be wise
> for dilution in the B&W version ...

The chemistry for thermal heads differs somewhat.  I suspect glop
would not be a good idea in an HP printer.

Have you seen any evidence of  the thermal heads getting hot and not
producing even plain, dense areas?  I've  heard that allegation
regarding the HP printers, but have no experience with such.

Paul
www.PaulRoark.com