Hi Roger
Not referring to uncoated offset paper specifically. I mention RC photo paper,
but it could also be more regular coated matt paper. But the paper type is not
very important for the argument, more what tint it has, often made worse by
OBAs.
I print photos, and when editing and printing, I sometimes prefer to get a
better absolute match on the colors than what relative intent does on bluish
papers with white point like b* -5 to -9. Here the paper's blue tint can be
seen throughout the image, not just on greys. The whole image lacks warmth. I
could of course use more neutral papers, and I do, but those are often high
priced fine art papers, and sometimes, for proof and/or lower cost, I print on
less neutral, typically bluish, papers. And here I would like the option to get
the color hues more accurate (as edited) and avoid the paper white skew.
Of course everything is then coated more or less yellow to compensate, as you
indicate. But colors do actually match better then, and only look yellowish if
you compare to paper white (which in reality is blue). So if you trim off
unprinted borders, the printed photo will match the edited file/monitor better
IMO. And I’d like to have the choice, as it can depend on mood, or pardon the
pun, intent, of the image.
But it isn’t absolute rendering exactly I want, as that could clip both shadows
and highlights (everything out-of-gamut of course), and I want to maintain
tonality there, as in relative with BPC or perceptual (but without whitepoint
mapping on either). I’ve tried manually to adjust images to avoid clipping and
then print with absolute rendering intent. That’s what I’d like to have readily
available in a profile intent, keeping my color tones more absolute, not skewed
to paper white. And it seems some providers like Hahnemühle does that in their
perceptual intent, and what i1Profiler likely makes possible with their
software. So how to do with ArgyllCMS?
Can I manually edit a profile somehow to achive this, change the "Grey axis
alignment factor” (perhaps requiring recompile) or?
/Henrik
On 21 Sep 2017, at 13.31, Roger Breton <graxx@xxxxxxxxxxxx> wrote:
Henrik,
Why would you prefer "absolute" grays as compared to "relative" grays on
uncoated offset paper?
My humble experience is that grays are "judged" relative to the paper color.
In my VERY humble opinion, if you try to make the grays "absolute", on
uncoated paper, I would argue that they will appear "yellowish" visually?
My two cents,
/ Roger
-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx] ;
On Behalf Of Henrik Olsen
Sent: Thursday, September 21, 2017 5:32 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Profile generation with perceptual intent with
compensation for paper white
I don’t have a license to i1Profiler, but notice in manuals it has a setting
called “Neutralize gray” for perceptual intent, and is described at
http://nativedigital.co.uk/site/2013/05/advanced-inkjet-profiling-with-i1-profiler/
as
The Neutralize Grey slider allows you to force the greys to become more
absolutely neutral by dialing in a lower value or match the paper more by
setting a higher value.
That seems to be what I want. Control over how paper white point is being
mapped. I’d like my (perceptual) profile to neutralize any offset in paper
white, typically blue, så my colors won’t have a blue cast.
Any way to come closer to this with ArgyllCMS?
I notice this Gamut Mapping Specification during colprof:
"Grey axis alignment factor 1.000000”
That could be an indication that the alignment could be turned down, so it
doesn’t become relative to paper white, but more absolute neutral…
Hope to get some input on this. Thanks.
Regards
Henrik
On 2 Sep 2017, at 21.02, Henrik Olsen <henrikolsen@xxxxxxxxx> wrote:
I’ve noticed that Hahnemühle's line of printer profiles differ from the rest
of (or most at least) the profiles I have regarding it’s perceptual intent.
If I take a paper/profile like their RC Photo Luster with a typical bluish
look with a Lab b around -9 the difference is clear compared to other
profiles for similar bluish RC papers. Without printing, but just
softproofing in Photoshop or Lightroom (with paper and ink simulation turned
on to primarily see effect of paper white point), it’s clear that typical
profiles maintain the bluish look of the this category of paper with both
relative and perceptual intent, and rightly so you might say, as they adapt
to the paper whitepoint.
But… I’ve sometimes wanted to print on some of this kind of paper, but
without getting the bluish tint to the images. Wishing more of an absolute
match on colors with my source file - not nessecarily super scientific
match, but a perceptual match, more as if the paper actually had a neutral
white point. So today I stumpled upon this Hahnemühle profile, and notice
it’s perceptual rendering does not appear bluish under softproof (as the
relative of course do), but visually matches impressively well with my
source image without a strong blue tint anymore - just as I wanted.
I know perceptual intent can have all kinds of custom unspecified tricks up
it’s sleeve, but as I have long had a wish of solving how to compensate the
bluish look when printing with my own argyllcms profiles (primarily from
Lightroom), I got very intrigued. Absolute intent isn’t available from
Lightroom, and doesn’t fit the wish anyhow, as I would like something like
black point compensation to be of use to me.
I tried making profiles with some of the alternative intents with colprof
(-t and -T) and had hoped something like “perceptual appearance” might do
the trick, but it doesn’t seem like.
So, any hints on how to compensate for a paper white color tint similar to
what that mentioned Hahnemühle profile achieves in it’s perceptual intent?
So I avoid the bluish look (in case I don’t print on more neutral papers for
various reasons). Not talking FWA compensation here btw.
The profile name is HFAPhoto_CanPro1000_PK_HahnemuehlePhotoLuster290 in case
you want to examine it.
Regards
Henrik
