Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Antonis 
Ricos" <antonisphoto@y...> wrote:

Antonis,

There are some similarities to IJC.  
There's a calibration page that shows each individual ink in 
a 21-step wedge laid out in percentages.  
1) You decide on ink limit percentages.
2) You print another page with your percents;
3) You just decide the order of inks -- dark to light and
   measure the density of in terms of the next darker one.
   This is just a density comparison -- absolute values are
    not used.   You end up with percentages like:
   Black = 100%,  Cyan=40%, Magenta=20%, Yellow=8%

This is all that goes into the partitioning algorithm.

After this you need to compensate for the dotgain.  This is
pretty much like what IJC calls linearization, but you only
have to do it for the already partitioned inks not the individual
inks.  I have some aids for this where you specify how much
"lightening" you need in the highlights and in the shadows
and a smooth curve from light to dark is generated.   It's
also possible to use Photoshop to make very steep dotgain
correction curve, but for the most part that's not needed.

Roy


> Roy,
> 
> 
> at what point (and how) in this process do you make a profile? 
> 
> Antonis
> 
> 
> 
> ......
> 
>  One of the pages is a QuadToneRIP page where you
> > select, first, that you want QuadTones, then select a curve or 
two if you
> > want blending.  Then print.  Naturally all these options that 
you've
> > selected can be saved as a named set for later use.  All the 
data is spooled 
> > and you're off working on the next image while that one 
prints.
> > 
> > All this stuff works from any program that can have grayscale 
images and
> > can print.
> > 
> > Roy