Setup Grey Point vs Channel Mixer picker?

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shijan
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Setup Grey Point vs Channel Mixer picker?

Post by shijan »

White Point (Setup Grey Point with unchecked "Fix White Point") vs Channel Mixer.
Both tools use color picker to automatically adjust channels to grey point. But i see small difference between these tools when use color picker and select same color patch on the photo.
Could anyone explain the difference between these tools when used to align channels?
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Martin Huber
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Re: Setup Grey Point vs Channel Mixer picker?

Post by Martin Huber »

In the channel mixer, the resulting R channel (as well as the resulting G and B channels) can be a combination of the orignal R, G and B.
Other functions don't offer this flexibility: The resulting R channel is just a modifcation of the original R channel

Martin
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shijan
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Re: Setup Grey Point vs Channel Mixer picker?

Post by shijan »

So Channel Mixer picker is formally "better" than White Point (Setup Grey Point with unchecked "Fix White Point") ?
I just attempt to remove orange mask from film scan, and align R G B channels to frame edge grey point. In most cases this operation usually done during scanning by adjusting RGB gain of image sensor, but i just attempt to reproduse the same digitally in most accurate way...
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Martin Huber
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Re: Setup Grey Point vs Channel Mixer picker?

Post by Martin Huber »

shijan wrote: Fri 06 Nov 2020 16:15 So Channel Mixer picker is formally "better" than White Point (Setup Grey Point with unchecked "Fix White Point") ?
It's not better, but it offers additional options in your situation.
shijan wrote: Fri 06 Nov 2020 16:15I just attempt to remove orange mask from film scan, and align R G B channels to frame edge grey point. In most cases this operation usually done during scanning by adjusting RGB gain of image sensor, but i just attempt to reproduse the same digitally in most accurate way...
AFAIK usually Curves is used for that.

Martin
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shijan
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Re: Setup Grey Point vs Channel Mixer picker?

Post by shijan »

I don't like the concept to set hard clipped pure black point with Curves. I prefer to set grey point (aka WB in RAW) and keep all dynamic range unclipped. Next i set black and white point with "AutoLevels" and recover back any amount of clipped data with "Output Levels" slider. In 32 bit mode "Output Levels" allow to bring back all clipped data. Still experiment with options...
PhotoLine UI Icons Customization Project: https://www.pl32.com/forum3/viewtopic.php?f=3&t=6302