I believe you're asking for


<http://bugzilla.gnome.org/show_bug.cgi?id=325564>which has been addressed
when using GEGL.


On Mon, Jul 26, 2010 at 6:33 AM, Charlie De <charlieco...@yahoo.com> wrote:

> Hello all,
> I've joined up with this list to make an important suggestion for
> improvement.
>  In short, the Color and Value blending, transfer modes in GIMP do not work
> as
> they should.  The problem is compounded by the fact that there seems to be
> no
> application on Linux where these transfer modes work correctly.  In fact,
> it
> seems all the major applications use the same or very similar algorithms.
>  So
> the problem is the same in Krita (which uses GEGL as far as I know) and in
> ImageMagick.
> To confirm the problem, try this:
> * Open an image in GIMP, preferrably one that has noticeable noise, and the
> noise should be coloured, not merely monochromatic.
> * Duplicate the image into a new layer and blur it, say by 5 points.
> * Set the transfer mode of the blurred layer to Color.
> What should happen is that the colour component of the noise should be
> eliminated, but the luminance/value should remain the same.  This is not
> the
> case, the result worsens the luminance noise!  If you have trouble seeing
> this,
> zoom into the image up to 400% or try an image with more obvious noise.
>  Also,
> try increasing the blur factor.
> Now by comparison, repeat the experiment in Photoshop.  You won't fail to
> notice
> that in Photoshop this works correctly.  The colours are more muted,
> perhaps
> 'leaking' over colour boudaries, but the luma noise is not made worse.
> The same effect is at play the other way round, if Value is used instead of
> Color (and it's the bottom layer that is blurred).  And the same effect is
> also
> at play if instead of layer blending, the blending is done in the Fade
> command
> dialog.
> In short, there is no correct way yet of using these transfer modes on
> Linux and
> a proper solution is desperately needed.
> By the way, I'm using GIMP 2.6.8.  I appreciate that 2.7.1 is using GEGL as
> will
> 2.8, but I doubt that will in itself offer the solution, because Krita is
> using
> GEGL and the problem there is the same.
> Thank you for listening and good luck with the coding.
> Charlie
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