Datacolor User to User Support Group.

on august 20 you gave me info on using the photoshop 225 target to use 
to calibrate 4 x 6 pics.
can you please check the photoshop target, as mine has a missing patch 
at row 10 column J.
any advice?
thank you, 
Shmuel

>on august 20 you gave me info on using the photoshop 225 target to use
>to calibrate 4 x 6 pics.
>can you please check the photoshop target, as mine has a missing patch
>at row 10 column J.
>any advice?

Shmuel,

The missing patch is supposed to be missing; it's paper white;
which is supposed to be measured that way.


Best regards,

-- 
David Miller
Senior Software Developer, Digital Color Solutions
ColorVision

David, just wanted to say thanks for your assistance while the color improvement on my inkjet was excellent, the effect on my 4x6 in dye-sub printer was

>David,
>just wanted to say thanks for your assistance
>while the color improvement on my inkjet was excellent,
>the effect on my 4x6 in dye-sub printer was actually quite poor.
>any thoughts?

I wonder if the issue could be in problems with enabling/disabling
color management in the printer driver?

If the dye-sub's driver controls for doing this are either less-clear-cut
than what's typically found in inkjet printer drivers; or non-existent;
then it's going to be difficult to accurately profile the device.

One question is: can you be more specific about "poor"?

When you make the target print (no color management) that should not only
be too dark/saturated, but probably also color shifted to a certain extent.
If the printed targets don't look like this, then that would mean color
management is still enabled in the driver. (Or another way of putting it:
target prints should definitely NOT look like their color is "right"). This
is what you would have already seen from your inkjet target prints.

Measuring this and building a profile should bring prints (through the profile)
back in the other direction. If not, then that would imply the profile isn't
being hooked in during the printing process.

If it's a question of accuracy (overall results look reasonable, but there
are color shifts in some areas, or grays aren't neutral enough, etc) then
that would be something that more patches would address.

>i read somewhere that dye-sub's benefited from the largest target.
>any plans on your breaking that target up into 4x6 in 'pieces'?
>it would be very much worth it for me to do this, if it means
>accuracy in profiling.

As with the 1-sheet 225 patch target, there's nothing to stop you from doing
this yourself. Open the corresponding .tif file from the Targets folder in
Photoshop; subdivide it into section; print them individually; and then
just make sure read the patches in the right order. There are 27 rows of
27 patches, and as you read them in, they'll all "nicely" drop into place in
the rainbow-ordered supergrid of 9 "sections" in the 729 patch target.

In fact, looking at the target this way, here's what I'd suggest: see if
you can get an acceptable print of each 9x9 "layer" onto a single sheet of
4x6. The first image would be rows 1-10, A-I; the 2nd image would be 1-10 J-R;
etc, for a total of 9 prints. You would need to hand-label these accordingly
and you would have to switch from print to print while reading the patches.
Not trivial to measure this way; every 9 patches, you'd have to switch to
a different print, which would mean 729/9 = 81 total target print swaps
while measuring the entire set. But it would work; as long as the sub-images
you print give you large enough patches on 4x6 to measure. Too small won't work.

The way to improve this in PFP would be to create an "official" target in PFP
that would support this more directly: print onto 9 or more pages, in such
a way that you would read the first page, then the next, then the next, etc.
(just like with the 3-page 729 patch target) until you were done. Not sure
how much priority we can give this in the immediate time frame, though.



>thanks again,

You're welcome!


Best regards,

-- 
David Miller
Senior Software Developer, Digital Color Solutions
ColorVision