Digital BW, The Print

----- Original Message ----- 
From: "Tyler Boley" <tyler@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Thursday, June 05, 2003 8:09 AM
Subject: [Digital BW] Re: IJC on w2k ...older macs on PC
network???


> You're talking features. Martin specifically asked about print
quality.
> I have a report of lack of ability to print a sharp edge at the
image
> border and an overall softness with IJC. I've seen the same
thing with
> Gimp at the edges, so I'm wondering if it's inherent in the
dithering.
> All these features are impressive, if one needs them. But if
someone is
> using an existing quad set that works well with the Piezo
plugin (for
> example) on papers they are happy with, and has no need for
these
> additional benifits, what are you gaining in terms of print
quality for
> your time and $$$?
> There's a question, again.
> Another question.
> More on topic, why would anyone go out and get an entire new
computer,
> install an operationg system quickly becoming obsolete, instead
of
> simply waiting for a version for for the platform they already
own?
> Another question.
> Although I don't use them, if someone is making perfectly
beautiful
> prints with RGB curves, why is it non-sense?
> Tyler

Tyler,

having a PC, the Wasatch SoftRip and an Epson 9000 I decided to
use that setup for Ultratone VM inks. One of the decisions in
curve control was whether the greys should be used to their full
100 % in each curve separation or let the next one take it over
at 90 %. I think much of the softness, lack of small detail is a
result of the right setting in that part of the curves and
related to the dithering quality of the driver. If the dithering
quality is excellent then you better end the curve early and let
the next grey take it partly over with low percentage ink and the
good dithering. The 90-100 % dithering is always harder to
control than any dithering in the 0-30 % part. It is also a
compromise on ink amount and the length of the greyramp covered
by one grey. The Wasatch doesn't have such a good dithering and
then the good compromise is harder to find. I still have to tweak
that part better as I see the problems you describe.

The work on the SoftRip neutral settings that I have done is as
follows: the magenta channel with the toner remains straight,
that channel is linearised (M+m in one calibration curve),
separation curves made for the YCcK channel greys and then an
overall linearisation with a greyramp without the toner printed
(as that one already was linearised), returned to the curves to
tweak them till the linearisation curve is almost straight, the
last linearisation curve is three times used: in the Y,Cc,K
channels. The greyramp with the toner checked for the
straightness in another linearisation curve measurement but that
one is only for control, I wish that Wasatch will give me that
extra feature of an overall linearisation that measures more
samples than the one that is used for one channel linearisation.
Now I use the 17 samples for the 4 = YCcK channels and that is
just 4 per channel, not enough. I could tweak the separation
curves of course but that probably introduces more problems than
it solves. The inklimit is set at 90% and the total made 60%
lighter (Wasatch units). that gives some slack for the other
curves.

Next to the fact that I still can use the old setup I have a
driver now that can be linearised (more or less, hope on better),
a good start for the other warmer, colder curves as that can be
done with the total curves and the toner (Mm) curve. The driver
is on another XP system and I throw
a simple straight CMYK 0-100% conversion of a greyscale file on
it that is made with a PS action. Yesterday evening I got a small
application that a friend has made which converts a 16 bit
greyscale tiff into a plain 16 bit CMYK tiff (it has to be
changed to LZW compression in default as that will make the files
much smaller). The SoftRip eats that and I hope it makes a
difference in the output though I'm not sure yet. Using the
application just before the RIP makes the transport on the
network easier and editing is done in the greyscale image on
another system.

In the process I made a linearisation target that is dedicated to
the Ultratone VM inks driven by the Wasatch. I have used
Spectrocam readings as my Gretag densitometer is not reliable at
higher Dmax anymore and the SoftRip is compatible with the
Spectrocam.

Another approach that is possible is the use of Paul's VM curves
cnverted to RGB profiles and the Wasatch paper-ink settings
adapted to the Epson driver. The Wasatch SoftRip can be made into
an RGB device though it is CMYK in default. That would allow
printing straight from a greyscale but I find it less transparent
and I guess that I can get more in this way.

Not a cheap solution of course but the RIP was there already for
other reasons. If there's a port to Windows of one of the
dedicated B&W drivers or Gimp-print itself then I think it should
be nice if it became the default driver for Qimage. The
combination of that print software with it's versatile
interpolation routines etc with a driver that is more transparent
and with good dithering will beat many RIPs around. I've used
Paul's curves on Qimage and the Epson driver and I see no
problems with the interpolation nor sharpness settings of that
software. The lower black D is then the only thing left to be
changed in my opinion and a Gimp-print port is the answer.

Ernst