Aaron,
« TTBOMK »? « To The Best Of My Knowledge”? Wow 😊
Looks like an interesting site.
/ Roger
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On Behalf
Of Aaron Perelmuter
Sent: April 29, 2022 9:26 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Print evaluation?
TTBOMK there still aren’t any RGB standards for print or proof accuracy, as
there are for CMYK with the various ISO12647, IdeAlliance, Fogra, etc
requirements for print and proof validation but I’ve found an incredibly useful
site who does exactly what it is you’re looking for, specific to RGB fine art
printing. Better still, the dE values they use are much more inline with what
most ‘typical’ fine art printers would expect from their profiles and prints.
As in, much lower than, say, the ISO12647 requirements.
And the best bit is that they provide extensive documentation, so much that
it’s super easy to duplicate their processes and procedures and the only thing
you miss out on is the convenience of being able to just measure some patches
and get a nice and pretty pdf with the results. But it’s easy enough to put
this info together by oneself and get the same end result, that being your
newfound knowledge regarding your printer and profile accuracy.
Check it out here:
www.colorcheck-online.de/en/report.html
<http://www.colorcheck-online.de/en/report.html>
Their English translations aren’t exactly the greatest, sometimes non-existent
but google translate does the job admirably. They provide all of the required
patch targets in a variety of layouts for various instruments and measurement
applications. They have extensive tutorials, how to section, free downloads of
the targets and more. I’m pretty sure you’ll find the site is exactly what
you’re looking for. I’ve been using their procedures for nearly 10 years and
they’re still just as relevant today as when they were released.
Let me know what you think.
Cheers,
Aaron.
On Fri, 29 Apr 2022 at 11:11 pm, Yves Gauvreau <gauvreauyves@xxxxxxxxx
<mailto:gauvreauyves@xxxxxxxxx> > wrote:
Roger,
I have no need for "proofing" especially if it means simulating a CYMK printer
on an RGB printer.
The patches they suggest we use are created to be printed on specific papers on
a CMYK printer or press, yes I know we could "proof" that to my RGB printer.
Why go through all this work around instead of going directly to what I want to
evaluate, an RGB printer printing an RGB image on the paper I want as
accurately as possible.
I want to know if it prints a black and white as black and white and as neutral
as the inks and the paper can achieve.
I want to be able to exploit as much of the gamut as is possible with my
papers. All the papers I used can exceed both Adobe RGB and sRGB colorspace in
some areas and yes the inverse is true as well.
Clipping may be acceptable to some, but I found this unacceptable and I prefer
a more elegant and refined solution. I think gamut mapping on an image by image
basis is the best approach.
I think every one will agree, there is no point to test a printer with values
that were used to create the profile. Furthermore, I would also think there is
no point on using out of gamut values either. Then, what should I use to make a
“good” set of patches, suggestions?
Let's say I use the criteria Roger suggest, 1.5 average and maximum 5 DE2000.
Would you suggest something specific to evaluate the neutrality and or the
chromaticity independently?
Any other point I should look for?
/Yves
Le 4/29/2022 à 8:12 AM, graxx@xxxxxxxxxxxx <mailto:graxx@xxxxxxxxxxxx> a écrit
:
IDEAlliance recommends DeltaE 2000 with some specific “ideal” numbers.
You could use the same kind of criteria.
For proofing, for instance, the average of the IT8.7/4 1617 patches has to be
within 1.5 and the max was below 5. I sometimes profile my Epson printer as an
RGB output device and when I use IDEAlliance criteria for proofing, I get the
expected values.
Depends what you want to proof.
/ Roger
From: argyllcms-bounce@xxxxxxxxxxxxx <mailto:argyllcms-bounce@xxxxxxxxxxxxx>
<mailto:argyllcms-bounce@xxxxxxxxxxxxx> <argyllcms-bounce@xxxxxxxxxxxxx> On
Behalf Of Yves Gauvreau
Sent: April 29, 2022 7:10 AM
To: argyllcms@xxxxxxxxxxxxx <mailto:argyllcms@xxxxxxxxxxxxx>
Subject: [argyllcms] Print evaluation?
Hi,
are there any standards to evaluate a RGB printer specifically? Something like
Ideal Alliance certification stuff maybe or whatever but for an RGB printer.
~Yves
