Thanks Aaron,
very interesting in deed, I'll have a look at this.
Many thanks again,
Yves
Le 4/29/2022 à 9:25 AM, Aaron Perelmuter a écrit :
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> 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 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
<argyllcms-bounce@xxxxxxxxxxxxx>
<mailto:argyllcms-bounce@xxxxxxxxxxxxx> *On Behalf Of *Yves Gauvreau
*Sent:* April 29, 2022 7:10 AM
*To:* 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
