I have to say, in the second example image I also preferred the fogra
profile. I didn't print the picture (probably sRGB so not really Fogra or
the luminance preserved rendering), but it looked better to me on my
macbook. I found the slightly more reddish color of the foreground off
putting. I wouldn't have expected that of the dry grass fields I grew up
around.
It sounds like what Samual wants is a tool to interactively select a
rendering between "pure luminance preservation" and "pure euclidian
distance to the color volume in CIELAB." Beyond the capabilities of a
single ICC profile which can really only represent one value on that scale,
and neither of which would reliably preserve the hunt effect or
helmholtz-kohlrausch effect which are critical components of our
visual response and depend on spatial details. As Graeme said ICC profiles
are not aware of the spatial frequency details in the image contents.
- Tucker
On Thu, Nov 28, 2019 at 8:41 AM Yves Gauvreau <gauvreau-yves@xxxxxxxxxxx>
wrote:
Roger,
see below.
Happy thanks giving to all of you and have a great day.
On 11/28/2019 7:52 AM, graxx@xxxxxxxxxxxx wrote:
Yves,Science Laboratory, headed by Mark Fairchild, is bound to be "valuable". I
You are on the right track. Anything coming out of RIT's Munsell Color
took some color seminar at MSCL, a few years ago, and learned a lot -- wish
I could take their Masters in Color Science...
Happy to see I didn't came across some foolish idea.
discovery. It is an "S" curve, easy to reproduce in Photoshop using the
The "sigmoidal" contrast function is one of Fairchild "popular"
Curve tool. I think everyone uses a sigmoidal function, in color
retouching, it's so intuitive.
I agree.
ink on paper can carry is severely limited compared to an emissive device.
As for "prints" vs "monitors", you are right, the contrast ratio that
I think I remember something like 200:1 but I'm not sure. The most limiting
factor is the "brightness" of the substrate itself. If you're lucky, you
use a glossy finish inkjet paper, if you're less lucky, you use a matte
finish paper. The other factor is the "Darkness" of the darkest blacks that
the paper can hold. On a sheetfed press, you see, they can hold anything
from 320% to 340% TIL, on a good coated paper. At that level, the CIE L*
value can go down to less than 10. A glossy inkjet paper can go down to CIE
L*= 5 or even less. That has a dramatic impact on contrast.
on the print. Everything being equal, the more, the better, but not all
The other most important factor is the illumination, the light falling
prints are viewed under direct sunlight, so there goes any chances of
"contrast". Museums use very low light illumination, like 32 Lux, to
preserve paintings, and 3500K!
The illumination factor is practically random unless of course you know
in advance where it will end up and its characteristics before hand.
point. They can work wonders but need to be tested. Who knows the details
"Canned profiles" are not man's best friend but they are a starting
of their construction? My Epson printer came with a shitload of ICC
profiles for all Epson's substrates. If I print through the Epson driver,
why not use those profiles as starting points? They ought to be good for
something.
I think the only way to be sure is to at minimum verify those "canned"
profile extensively. Or build them yourself of course, this mean you
have to know what your doing right?
Regards,
Yves
On Behalf Of Yves Gauvreau
/ Roger
-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx>
Sent: Thursday, November 28, 2019 7:36 AMbecause a breach of trust would very costly to them. Seems I may be wrong,
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Rendering intent?
Roger,
I was under the impression that I could trust the manufacturers profiles
but I'll have to verify myself before accusing anyone. It would obviously
explain a few thing.
color right is only part of the challenge I would think. Take the change in
I though of doing pretty similar to what you suggest here but having the
contrast that is most likely to happen from display to the print itself, I
don't see how it would not affect the "appearance". Maybe the profile I
use are so so, I don't know yet I haven't verified but way to often, when I
print the result are not as "wow" as I would like. Can I improve on that, I
don't know but I'll try very hard.
Enhancement Functions" @ http://rit-mcsl.org/fairchild//PDFs/PAP07.pdf
I found a paper here "Image Lightness Rescaling Using Sigmoidal Contrast
the concept which remind me of tone mapping a little bit. We have a
I'm not qualified to judge whether it's a good idea or not but I like
relatively high dynamic range image on our display and a relatively low
dynamic range on our paper. Finding a path between the two that preserve
the "appearance" as much as possible seems a good starting point. I'll
investigate this further. But for now, the electricity is going off and on
here, so that's it.
then the result can be
Thanks,
Yves
All of this is like an orchestra, if everyone plays his part in sync
profile construction.
On 11/27/2019 1:24 PM, graxx@xxxxxxxxxxxx wrote:
Yves,
If your objective is to "Convert the "magic" you see on your display
on a piece of paper" then that's a good definition of the problem.
Naively, I would say you have two possibilities. Either you make sure
the gamut of your "piece of paper" is able to hold all the colors your
display shows you OR you make sure the gamut of your display "fits"
inside your "piece of paper", regardless of rendering intents or
spaces.Is that a fair statement of the problem?
/ Roger
-----Original Message-----
From:argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx>
On Behalf Of Yves Gauvreau
Sent: Wednesday, November 27, 2019 8:56 AM To:argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Rendering intent?
On 11/26/2019 10:44 PM, Graeme Gill wrote:
Yves Gauvreau wrote:handling stuff as well.
Hi,
This is one off me biggest concern, who and which software can I
trust to do the work properly. I already know PS does many thing in
our backs that are questionable, others that are inaccurate, etc. So
I would be surprised if I shouldn't trust some or all their color
the only way of getting exactly what you want, is to do it the waywant.
you
Trusting any software with automatically gamut mapping to suite yourI already figured this one out.
particular sensibilities is likely to result in disappointment.
There are many more tools available to you manually, than are
possible with the sort of spatial independent mapping achievable via
ICC profiles and similar. Automatic, spatial independent mapping is
at its best when converting between different output referred color
the full size final image.On the other hand, achieving the best possible result starting withIf I understand correctly, in the context of artistic photography
raw, input referred photographs typically require human judgement as
to what is important, and what the desired end point is.
especially, there is only so much an ICC profile can do for us and of
course there is no such thing as a one size fit all solution either.
Converting the "magic" we see on our display on a piece of paper, is
our soul responsibility, right? I know the answer but it sounded nice
to say "right".
That practically mean we would have to create a "good enough" profile
to make sure it as all the qualities we need to go further, hopefully
we could use this profile as a starting point via a look at the
softproof image, knowing it's not the final version, do some edit,
some adjustment and print a small version to see if we need more
adjustment or not, repeat these step until you got it right and print
Thank you very much for all this Graeme.
Yves
Cheers,
Graeme Gill.
