I did try the suggestion as per Tobias and indeed it produces a pleasing
result. Thank you Tobias...
I experimented with sRGB clipping and looks like it pushes towards
purple while linear Rec2020 RGB pushes towards blue.
What I am learning (together with the gamut clipping) is the assumption
made by some modules. I certainly did not expect it.
Thank you again Johannes and Tobias. Yes - after 30 years (with
computers and graphics) still there is something new :-)
Regards,
B
On 2017-05-17 11:47 AM, johannes hanika wrote:
30 years young! could you please try what tobias suggested? the
slightly longer answer is that Lab is an interesting colour space, so
is your camera rgb. the colour matrix produces mostly matching colours
for usual tones, but due to the linear approximation this matrix
represents, it pushes out colours that are considered less important
(the blues in this case).
these out-of-gamut/imaginary stimuli result in negative L values in
the pipeline. that's a non-issue if you just convert to Lab and back.
as soon as you enable any module that makes reasonable assumptions
about Lab (like, L >= 0), you'd clip the values to the gamut of Lab,
resulting in the purple cast.
hope that helps.
j.
On Thu, May 18, 2017 at 6:26 AM, I. Ivanov <[email protected]> wrote:
In 30 years - I have never seen a graphic program of any kind to behave in
such a way and it would be considered "normal". The only settings available
are brightens, contrast and saturation and they are not altered by any
number. There should not be any change to the image.
Regards,
B
On 2017-05-17 11:16 AM, [email protected] wrote:
On Wed, 17 May 2017 11:11:43 -0700
"I. Ivanov" <[email protected]> wrote:
My expectation is that if I am to enable the module and do not
modify any of the values - brightness / contrast or saturation - all
of them remain zero - then it should not alter the image (but it
does).
I think that it is not a "correct" expectation.
1. If it was, then all modules would be enabled all the time.
2. All modules have default values and/or effects. Enabling the
modules should apply these values/effects.
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