Hi Babak,
The high UV blocking of the cyan ink could be due to the BLB tubes. It could
also be due to the negative substrate you are using. I would suggest that you
test to make sure you know the cause before more testing.
Assuming the high UV blocking in your workflow is due to the BLB tubes, and is
consistent, I would propose the following profile for a single value gray
system where all values follow the K. The Ink Level of the PK, C, Y and LK are
set to more or less give equal UV blocking at any point on the x-y coordinate,
based on the palladium print from the ink separation negative you linked to.
To test, you would install this profile and print a 21 step wedge negative,
then make a print with your standard exposure time, as determined with PDN. You
would see one of three conditions.
1. The print is perfect, with paper white at Step 0%, and maximum density at
100%, and clear discrimination at every step from 0% to 100%. If this is the
case, you proceed to the linearization stage
2. The print is too high in contrast, with many steps at paper white. If this
is the case, you would need to decrease the Ink Level limit of the PK, C, Y and
LK by the same percentage, and test again. This could be 5%, 10% or 20%, the
only way to know is to test.
3. The print is too low in contrast, with no paper white. If this is the case
you would need to increase the Ink Level limit of the PK, C, Y and LK by the
same percentage.
In any event, before you can linearize the profile (map the input/output
values) you will need to adjust the ink limit level to produce a print with
paper white at Step 0%, and maximum density at Step 100%.
You could also use the Carbon 100 profile, and just set the Cyan limit to 1, and do the three steps above to determine ink level limits.
Hope this information is useful. If not, you may want to look in the main QTR folder and read some of the docs on how to use QTR. Unfortunately virtually none of this is directed toward the creation of digital negatives.
Sandy
#PRINTER=Quad4880
GRAPH_CURVE=YES
N_OF_INKS=8
DEFAULT_INK_LIMIT=100
LIMIT_K=15
LIMIT_C=20
LIMIT_M=1
LIMIT_Y=25
LIMIT_LC=1
LIMIT_LM=1
LIMIT_LK=35
LIMIT_LLK=1
GRAY_HIGHLIGHT=1
GRAY_SHADOW=1
GRAY_GAMMA= 1
CURVE_K= "0;0 100;100"
COPY_CURVE_C=K
COPY_CURVE_M=K
COPY_CURVE_Y=K
COPY_CURVE_LC=K
COPY_CURVE_LM=K
COPY_CURVE_LK=K
COPY_CURVE_LLK=K