[argyllcms] Re: Neutralize Grey Axis
- From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 11 Jan 2011 11:14:59 +0300
Graeme Gill wrote:
> Given that D50 is a constant assumption in ICC, then I guess this effectively
> translates to an assumption of a spectrally flat reflective media ?
> [ie. a media that has a D50 white point when illuminated with D50.]
>
> But the reality is that the observer has no in built neutral reference,
> and adapts to the viewing situation, so I'm not clear on the circumstances
> in which rendering as if in an absolute colorimetric mode with the source
> being a spectrally flat media, gives a visually desirable looking neutral.
>
> If the output media has a cool white point itself (ie. lots of FWA), then
> the neutrals would look too warm. If they don't look too warm, then
> the observer must be adapted to something other than the output media. What
> are they assumed to be adapted to ?
The viewer can likely be adapted to illuminant or to the other images (paper
white). For example, a lot of prints at the
moment in viewer's field of view. It's critical for photo-exhibitions with B&W
images. In such cases the paper white
cromaticy is more important than brightness. So the approach is absolute RI,
which "repair" paper white by cost of
brightness. Another way (I hope) - change the viewing conditions in profiler,
for example:
colprof -iD50_1.0.sp -o1931_2 -f -qh -cmd -ds:n -dw:.345669:.358496 -da:100
-db:20 -dl:170 -df:1.5 -df:.345669:.358496
-S"sRGB.icm"
Other related posts:
