Roy,
I thought the 2-bit VSD mode had three drop sizes? The bits would be no-dot, 00, then 01, 10, and 11, right?
It appears the relative drop size ratio is printer and mode dependant as well. Some Epson stuff here. http://www.epson.co.jp/e/technology/sankei_4.htm
Best regards,
John Moody
-----Original
Message-----
From: QuadtoneRIP@yahoogroups.com
[mailto:QuadtoneRIP@yahoogroups.com]On Behalf
Of Roy Harrington
Sent: Saturday, August 20, 2005
9:48 PM
To: QuadtoneRIP@yahoogroups.com
Subject: [QuadtoneRIP] Re: QTR
51-step linearisation
--- In QuadtoneRIP@yahoogroups.com, "Tyler Boley"
wrote:
> --- In QuadtoneRIP@yahoogroups.com, Ernst Dinkla
...
> snip...
> > The targets you mention are the ICC profiling targets that
usually
> build
> > on linearised inkchannels. Linearisation targets exist in many
shapes
> > CMYK-CcMmYK-Ncolor and they have ranges of 11 to 41 patches per
> > inkchannel. the lowest number can be used for printsystems that
> actually
>; > address the heads separately but on a CMYK driver that is
linearised as
> > CMYK but drives a CcMmYK printer it is better to use the 21
patches so
> > there are 10 steps measured per head. With the 4800 that has 3Ks
you
> > could go up to 31 steps and that has been used for Colorspan
models
>; that
> > have 3 ink dilutions of CMYK each = 12 heads.
>
> My impression of the process is a bit different, correct me if I'm
> worng. Individual ink components of a color, C and c for example, or
> the 3Ks you mention, are generally not addressed individually in the
> linearization process. Some control is usually given with
respect to
> how the transitions will happen, but then the color (all inclusive
> "C", or"K") is linearized as one. How exactly the
total patch count
> may divide up between those indivicual components may not be very
tidy.
> I'm sure this varies from RIP to RIP. I recall Roy asking if we
> thought there would be an advantage to individul ink linearization,
> and wonder the same thing myself.
>
.....
>
> no doubt. But the partitioning step needs to be considered as a major
> part of the overall performance picture. How many patches and how much
> work needs to be done at the end can have a lot to do with how well
> behaved the ramp is to begin with.
> That few have trouble with QTR speaks well of Roy's existing
>; partitioning scheme. Setting it up to pull 7 inks in and out without
> major problems must have been fun, or not!
> Tyler
The 7 inks for K7 worked just fine. The partitioning code has been
the same
since day one. I thought about more levels of linearization but I'd
probably
do it after the partitioning rather that before with each ink.
But it's interesting that with the K7 inks its noticibly (but not much)
better to use
2880dpi with only one dropsize rather than 1440dpi which is using two
sizes.
I think its because the 2X difference in drop size is as big as the
difference
between ink densities.
Roy