## Graff desaturation

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### Graff desaturation

Hallo. I use Graff 1.0.24, and it looks like the desaturation algorithm performs not properly. I just compared the desaturated image with the same image after the desaturation in GIMP. Should I commit the bug report on that ?

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### Re: Graff desaturation

Currently we use the following desaturation algorithm: C = (R + G + B) / 3.
Before committing a bug, I suggest to discuss desaturation here.

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### Re: Graff desaturation

Photoshop uses the following approach. In the gray value of the pixel should the luminance be written. It is calculatd as average sum of the maximal and minimal color channel values.

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### Re: Graff desaturation

The difference can be illustrated here:
Original Photo
face_org_3.jpg (8.72 KiB) Viewed 10975 times
Desaturated Photo
face_bw_3.gif (71.81 KiB) Viewed 10975 times

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### Re: Graff desaturation

Maybe it will be better example:
color_table_org.jpg (17.78 KiB) Viewed 10970 times

color_table_4.gif (72.81 KiB) Viewed 10970 times

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Posts: 157
Joined: Tue Dec 16, 2008, 20:52
Location: Hannover, Germany
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### Re: Graff desaturation

Starting from the version 1.0.30d we have corrected the Desaturate function. Now it produces the same result as in Adobe Photoshop. Basically this function, now uses the Hue/Saturation functionality, i.e C = [Min(R, G, B) + Max(R, G, B)] / 2.
To achive old result, i.e. C = [R + G + B] / 3, please use function Black & White with default settings.

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