Digital BW, The Print

----- Original Message -----
From: "Julian Thomas" <julianthomas@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, December 30, 2002 2:47 PM
Subject: Re: [Digital BW] Colorbyte and Ink questions


> This is one of the big plusses of the Posterprint RIP. First you linearise
> the RIP for each inkset, then you can tweak the black laydown, then you
> profile for each paper/ink combo. So you get a driver that doesn't
compress
> tonal values and then optimum black flow and then profiles to much the ink
> to the paper. A major difference between this and IP IMO - you never wait
> for 'support' for an inkset - you just calibrate and go.
>
> Julian

It is a big plus of many RIPs. On the other hand it isn't so easy to make
CMYK printer profiles. "RGB" printer profiles are far easier to make. The
Wasatch SoftRip allows the user the usual linearisation (calibration in
fact) per printer/inkset + inklimitation + setting for the Cc/Mm breakpoint.
On top of that you can build CMYK printer profiles that incorporate the
Black Generation percentage and the kind of BG. You need a good profile
generator then.

With version 4.5 there is a choice added to use the printer as an "RGB"
machine, still with the basic calibration aspects but with an extra,
separate Black Generation setting that allows you to use "RGB" printer
profiles instead.
They actually added that to profile the more complex CcMmYKOG printers. With
their normal CMYK channel profile structure it wasn't easy to get the best
from those machines. Another approach would have been to make multiple
channel profiles and a colourengine that can handle that. Profile creation
software for that kind of colour management will be much more expensive. As
I understand it they are also working on that together with Monaco.

For B&W, good calibration and the use of curves in the driver itself should
be an advantage. The Wasatch SoftRip has the last as well. Still not enough
experience with that however. I have ordered the last upgrade and that
allows me some extra support. I wonder whether they could make a monochrome
linearisation for quad and hexatone inksets. A menu structure that allows
the user to set the quad channels from light to dark and a single greystep
for measuring. The measured results can then be translated in curves for the
individual channels. I guess that for a VM set two greysteps for measuring
would be needed. A CcMmYK printer is  linearised as a CMYK printer so in the
calibration curves you will see the usual breakpoint where c goes to C.
Something similar will then be seen in the single calibration curve for a
quad while the individual channels will have odd curves.

Ernst