Digital BW, The Print

----- Original Message ----- 
From: "Paul Roark" <paul.roark@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Wednesday, November 12, 2003 7:14 PM
Subject: RE: [Digital BW] QTR Ultratone Dmax on PhotoRag ?


> >... I'm back to the Wasatch SoftRip for quad printing. ...
> >The Eboni black in all the 4 curves is at least 1.85
> >on PhotoRag, ...
>
> Wow, maybe I ought to look into this RIP.  That's a fantastic
dmax for matte
> paper.

Well, I'm not so sure anymore about that number and not sure
about any number anymore.

I didn't trust the densitometer that much so I used the Kodak
Reflectence Density Guide next to it. Both readings were almost
identical with the old Gretag D142-3, the 2.00 patch of the Kodak
and the black printed. Kodak doesn't give a guarantee that it is
exactly 2.00 D. This morning I measured the same patches with the
Spectrocam and get much more difference between the two readings.
The densitometer is very much influenced by the gloss versus
matte readings, matte readings end up too high, that even shows
up on two different Kodak reflection guides where one is more
matte but should be 0.5 lower in density and ends up higher.
Could be that this meter needs a polariser and then can be
calibrated correctly. I actually don't trust the Spectrocam
either when it has to read into 1.8 to 2.0 territory. Stays about
0.07 to 0.1 below what it should be. 1.65 to 1.68 D status T are
the readings.  This also means that the linearisation with the
Spectrocam into the darkest samples can't be correct. Not that
much of a problem as it should make the steps wider in that area
if the Wasatch isn't compensating the SpectroCam readings.

With the Spectrocam a Generations 4 (black ink only) printed with
the Wasatch RIP is reading slightly higher than the Eboni black
(cool curve), the Gretag gives a much higher reading for the
Eboni black sample made with the cool curve. Both matte samples
on the same paper. To the eye the blacks are indentical in
density but Generations a tiny bit cooler. Outdoors, tungsten
halogeen and 5500 K light. Jerry Olson was right to use
Generations at that time, did he use the PressReady RIP then to
get beyond the Epson driver black ink limit ?

The only thing I trust now is my eye looking through the Kodak
guide punches on the sample and shifting the light falling on the
samples from reflection to diffuse. The black is near 1.8 D.

The subject had a question mark and I'm still wondering what QTR
should deliver in Dmax to get some reference. Especially the
"grey boost" to the black should give something similar in
density or even better.

Ernst