Datacolor User to User Support Group.

Hi all

I have been generating profiles with spyder3print for use with canvas
on a Epson 9880. 

When using a rendering intent of "perceptual", I get clipped shadows
on the monitor ( CS3 soft proof) and on the print. This manifests
itself as jet black patches/blotches in the darkest areas of the print.

When I use a rendering intent of "relative colorimetric" and "Black
point Compensation" is switched on, I don't have the clipping problem.

Q: is there something that needs to be done while profiling to set the
printer black point for "perceptual" rendering intent.


Thanks ...ed.

On Aug 8, 2008, at 5:00 AM, canvaspic wrote:

> Hi all
>
> I have been generating profiles with spyder3print for use with canvas
> on a Epson 9880.
>
> When using a rendering intent of "perceptual", I get clipped shadows
> on the monitor ( CS3 soft proof) and on the print. This manifests
> itself as jet black patches/blotches in the darkest areas of the  
> print.
>
> When I use a rendering intent of "relative colorimetric" and "Black
> point Compensation" is switched on, I don't have the clipping problem.
>
> Q: is there something that needs to be done while profiling to set the
> printer black point for "perceptual" rendering intent.
>
> Thanks ...ed.
>


Our recommendation is to leave black point compensation turned off when
softproofing and printing through our profiles. (This yields a deeper
black; and there should be no clipping in the shadows).

Also, our recommendation is to use the Saturation intent, unless you
see that there are out-of-gamut colors that are changing noticeably in
the softproof. Going to Perceptual will introduce some color mixing to
alleviate this, and going to Relative Colorimetric will introduce the
most color mixing.

If you're getting blotches in the shadows, it could be that there's
something wrong with your measurements (if you can use File:Open
Data in Spyder3Print, and email a copy of your measurement .xml
file to me at davem@..., I'll be glad to have a look;
just make sure you send me the MEASUREMENT FILE (.xml text file),
not the PROFILE that you've built from the measurements).

It could also be that the media settings you're using in the 9880
driver are totally blocking up the shadows; if you're putting down
too much ink, there's no way that profiling can fix this (seeing
the measurements will help diagnose this). You may need to use
different settings in the 9880 driver when printing the target
(and then later, when using the profile) to prevent this.


David Miller
Senior Software Developer, Digital Color Solutions
Datacolor

I get clipped shadows
> on the monitor ( CS3 soft proof) and on the print. This manifests
> itself as jet black patches/blotches in the darkest areas of the print.

Hello!

Another good thing to check, is if you're using the right media setting to print your target.

The best media setting to start with when printing with canvas is "Watercolour Paper - 
Radiant White". It may look strange but it is a plain fact.

If you don't use the right media setting, then your printed target can be far from the ideal, 
causing some problem in the profile at the generation step. Of course, we're speaking of 
extreme case here. While it is very rare to get a bad profile with S3Print, I have seen 
situation similar to yours with canvas when the media setting was really wrong or canvas 
print quality was very bad (clogged) in the dark tones (usually due to a poor quality 
coating used on the canvas).

I would suggest that you print the S3Print quality check target et that you complete the 
media setting quality steps and be sure that you get a decent print. You may also have to 
play with ink density setting in the 9800's driver. When you will be sure that you're going 
to print the best possible target (not clogged in dark tones), then go with it, print it, let it 
dry completely (a good 2-4 hours). Use the 225 patches + grayscale target. Many canvas 
on the market doesn't print very well in dark tones. You should get a very decent profile 
with 225patches + gray, with S3Print and then if you want ultimate accuracy you can use 
729 patches + gray later.

I routinely created profiles for canvas with S3Print software and I get great results. As long 
as you print on a decent quality canvas and use the correct media setting/ink density, it 
will work.

Daniel Vézina
Numart Inc.
QC, Canada

A huge thanks to the very knowledgeable people who took the time to
reply. I intend to try all your suggestions including using the
saturation intent and proofing using the watercolor media setting...
thanks.
David has been looking in detail at my measurements and passing on his
knowledge ....Kudos. 

For those interested. I posted crops from an image, a screen grab from
the softproof and a scan of the printed canvas, here:
http://www.flickr.com/photos/29419644@N07/sets/72157606653047144

I have exaggerated the clipping on the softproof so you can see the
effect. 
The canvas is "Breathing Color's, Chromata White(tm).


Since I posted, I have tried a number of test strips with the printer,
including a stepwedge from RGB 0:0:0  to 34:34:34. I am happy that the
printer doesnt have a tipping point where the blacks clip or block. So
I think it is down to the way that the profile interacts with
photoshop/qimage. With that knowledge ...I can avoid clipping by
shifting the levels in photoshop until blocks dissapear. Not ideal
...but a solution for now.

I will reproof with the watercolor media setting next. I will update
with any findings.


Thanks ....ed.