QTR-Quadtone RIP

Hi Piet,

There are a couple of issues here.

1) the density reversal is likely due to too much ink.    the default 
ink limits of 60 is OK
but the BOOST of 95 is the problem.   try BOOST=70

2) when printing steps or targets for linearization or ICC profiling, 
never use any color management.
so don't convert targets and don't print with a ICC profile.   this is 
a general rule for QTR and other
profiling methods.

3) With QTR never use an ICC printing profile from some other source 
like:  RGB1998 or color ICC profile.

4) I notice you are only using integers for the GRAY_VALs -- you can 
use decimal numbers here, too.
Something like   GRAY_VAL_7=1.2   is legal.

Roy

On Monday, January 22, 2007, at 08:13  AM, Piet Weber wrote:

> Hi,
>
> When I try to linearize my printer/paper/ink combination (2100/Innova 
> Photo Smooth/
> Piezography K7neutral), I run into a problem. This inkset has 7 shades 
> of grey.
>
> First, I have made the descriptor file, which I copied at the end of 
> this post. After I have
> processed this file, I open the Step-21-gray.tif image in the Eye One 
> folder and convert it's
> profile to QTR-RGB Lab. Then I print this file, using the QTR-RGB 
> matte paper profile, and
> select the newly created .quad file. The print looks okay, but it 
> needs to be linearized. I
> read the density of the patches (X-rite 408). Up to the 95% patch, the 
> density increases
> (95%=1.64). So fas no problem. But the 100% patch drops in density to 
> 1.55. How can this
> happen? The ink separation print gives me 1.68 for the most black K 
> patch!
>
> I have also tryed to print the file with the RGB1998 profile (instead 
> of QTR RGB Lab) and no
> printer profile: same result. I did create profiles in the past, with 
> good results, but this is
> new to me.
>
> I could spend hours finding the problem, but someone must have 
> experienced this before.
>
> Anyone?
>
> Cheers, Piet Weber
>
> PRINTER=QUAD2100-PK7
> CALIBRATION=NO
> GRAPH_CURVE=YES
>
> DEFAULT_INK_LIMIT=60
>
> LIMIT_K=
> BOOST=95
> LIMIT_C=
> LIMIT_M=
> LIMIT_Y=
> LIMIT_LC=
> LIMIT_LM=
> LIMIT_LK=
>
> N_OF_GRAY_PARTS=1
> GRAY_INK_1=K
> GRAY_VAL_1=100
>
> GRAY_INK_2=LK
> GRAY_VAL_2=30
>
> GRAY_INK_3=C
> GRAY_VAL_3=21
>
> GRAY_INK_4=LC
> GRAY_VAL_4=11
>
> GRAY_INK_5=M
> GRAY_VAL_5=4
>
> GRAY_INK_6=LM
> GRAY_VAL_6=2
>
> GRAY_INK_7=Y
> GRAY_VAL_7=1
>
> GRAY_HIGHLIGHT=6
> GRAY_SHADOW=8
>
> GRAY_GAMMA=1
> GRAY_CURVE=
>
> LINEARIZE=
>
>
-
Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com