QTR-Quadtone RIP

I am confused about creating an ink setup for my Epson 2200 printer 
using MIS UT7 inks for Condor BriteWhite paper.
In the User Guide I have determined my ink limit to be 85%, set my 
slider to that and reprinter the calibration page and found Lt gray 
to be 24% of Black.

Not I'm confused for the next step. The User Guide says in the Ink 
Density Calibration Section, "..QuadTone inks, this process is 
repeated for each lighter ink, comparing it to the next darker ink, 
calculating its density relative to that ink and then converting it 
to a density relative to black."

Later in the Creating a Non-Linearized Curve Section it says, "For 
QuadTone inks there can be more gray inks so you would repeat this 
process, setting the density of each gray ink relative to black."

My questions are:
1. Do I measure the 100% density for Lt Magenta relative to Lt Cyan 
(next lightest to next darkest) and find the % on the Lt Cyan stip 
that matches? Then find that density on the Black Strip and determine 
the percent? If so, why measure the Lt Magenta RELATIVE to the Lt 
Cyan? What does this do to know the % that 100% Lt Cyan is to Lt 
Magenta, wher is that used?
OR
2. Do I work up the lightness strips, Lt Magenta, Lt Cyan, Yellow, 
Magenta and Cyan and determine their respective 100% density values 
to Black to determine that % Black.

Thanks in advance,

Frustrated in Florida,

Tony

Tony

In the qidf file (or in the QTRgui Curve Creation page) the ink
densities are all expressed as a percentage of black. In his original
notes for QuadtoneRIP, Roy suggested that each black ink be measured
relative to the next darker black ink and then the percentage of black
be calculated.

For example suppose LLK had 20% the density of LK, and
                    LK had 40& of the density of K
then LLK has 8% (20% of 40%) of the density of K

The reason Roy originally suggested this method (I think) was that he
was simply using his eye to compare patches and estimating where in
the 5% step between patches the lighter ink fit. With a densitometer
it is probably just as easy (and accurate) to measure each grey ink's
density relative to K directly.

With regard to what inks to compare, your best bet is to look at some
existing UT7 curves to see how the inks are used. Make sure you look
at curves for the type of paper (matte or glossy) you are planning to
use. Also, the use depends on the type of K ink you are using. For
example curves for an inkset using PKN as the K ink would be different
than those for an inkset where the K is Eboni. Since use Eboni, the
following assumes you are too.

For glossy papers the K and LK are not used. Instead two curves are
made one warm and one cool. A neutral hue is achieved by blending the
2 curves. The warm curve uses the C and LC as grey inks and a little
bit of M is used in the deep shadows to improve dmax. For the cool
curve the M and LM are the grey inks and a little bit of C is used in
the deep shadows. In these cases the C (or M) is effectively the
"black" ink and LC (or LM) is the light black. Thus you need to tell
QTR the density of the LC (or LM)relative to C (or M).

For matte papers the K is used as well but the LK is not. So the warm
grey curve is formed by K, C and LC and the cool grey curve is formed
by the K, M and LM.In this case you effectively have 3 black inks so
QTR needs to know the density of C and LC relative to K (or M and LM
relative to K).

The LK is normally only used when printing with the Epson driver a la
EZBW mode. If you print only with a RIP you could use the LK position
for something else.

Hope this helps. 

Tom Moore 

--- In QuadtoneRIP@yahoogroups.com, "stasunas" <Astasunas@...> wrote:
>
> I am confused about creating an ink setup for my Epson 2200 printer 
> using MIS UT7 inks for Condor BriteWhite paper.
> In the User Guide I have determined my ink limit to be 85%, set my 
> slider to that and reprinter the calibration page and found Lt gray 
> to be 24% of Black.
> 

...

> 
> Frustrated in Florida,
> 
> Tony
>