Re: [Gimp-developer] 'gimp-levels' procedure with GEGL activated.



> Date: Sun, 15 Jul 2012 13:37:27 -0400
> From: l elle stone gmail com
> To: exposito ssp infomed sld cu
> CC: gimp-developer-list gnome org
> Subject: Re: [Gimp-developer] 'gimp-levels' procedure with GEGL activated.
>
> ...But Levels with "Colors, Use Gegl" checked affects the midtones more
> than the shadows. The difference is noticeable with an sRGB image,
> drastic with a linear gamma image.
>
> Elle
>
> --
> http://ninedegreesbelow.com
> Articles and tutorials on open source digital imaging and photography
> _______________________________________________
> gimp-developer-list mailing list
> gimp-developer-list gnome org
> https://mail.gnome.org/mailman/listinfo/gimp-developer-list

Go to the Curves tool and adjust the white point down to 128.  This should darken the image by 50% (eyedropper verifies that white is now 50% grey), however if you do the same with Colors > GEGL activated then your results are quite different - instead of coming out at 50% grey, the same white pixel now comes out at 22% dark grey - which is clearly incorrect behavior.

But it's also conveniently about a 0.45 gamma correction from the correct value....

-- Stratadrake
strata_ranger hotmail com
--------------------
Numbers may not lie, but neither do they tell the whole truth.





[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]