[argyllcms] Re: Profile generation with perceptual intent with compensation for paper white
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Fri, 22 Sep 2017 10:47:27 +1000
Henrik Olsen wrote:
But I guess we also adapt to the surrounding light and known colors around
us, and
therefore can spot a bluish paper/print lacking the relatively warmer tones I
edited
the images in.
Not usually, no. Adaptation is complex, part of it being in how the receptors in
the retina automatically adapt, part being how the opponent signals derived
from the receptors make us sensitive to white balance, and ultimately there
is a cognitive component striving for Color Constancy. In my experience
this all adds up to an ability to almost completely disregard the
color of the paper in the context of comprehending an image, even with
highly tinted papers. You can manipulate these mechanisms though, by
introducing other white cues, or eliminating the perception of there being
an image.
So the question I would be asking is: if your viewing environment
is making you aware of the slightly blue nature of the paper, does it
reflect a realistic viewing condition ? I would suspect not.
[ And I am very familiar with FWA loaded papers, having dealt with them
extensively in the context of color copier color management. 99.99% of
the office copy paper that you will come across is low quality paper
loaded up with FWA. As I write this, my desk is littered with such
paper (M0 D50 b* = -9.25) , and none of it looks blue. On the contrary,
if I introduce a piece of Tyvek which I know to be a very highly reflective,
uniformly spectrally reflective white into my field of view,
it looks quite yellow. Now if I filled my desk with pieces of
Tyvek and introduced one piece of Office paper, I'm sure the
reverse would be true :-) ]
And if you do shift the white of the image on the paper by skewing
it to the yellow, you will find that the resulting image is much more
susceptible to changes in illuminant color and UV content.
I can see a big difference between my images printed on neutral paper and
images
printed on bluish RC papers, using relative col.
If you put them side by side, then yes, of course you will. But does that
reflect a realistic viewing condition ?
So I see great value in an ability
to control the neutrality of perceptual intent, but cannot find a way to do
so with
ArgyllCMS - which I otherwise love.
I've suggested a means of achieving what you want (collink -iaw) - give it a
go, and see
if it works the way you expect.
Graeme Gill.
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