On Wed, Jan 07, 2004 at 09:43:09PM +0100, Sven Neumann wrote:
> Hi,
> David G??mez <[EMAIL PROTECTED]> writes:
> > I've scanned some jpeg images with a 24bit depth. Some of them are old
> > photographies in black&white that show 'bands' when are displayed on
> > a 16 bit depth display. After digging in the menus i noticed that the
> > image could be transformed to a indexed pallete, with a Floyd-Steinberg
> > dithering, but that did not solve nothing, the maximum number of colors
> > cannot be set to more that 256 :-/. Is there another way to dither an
> > image in gimp? Programs like gqview, an image viewer, use the dither
> > algorithms bundled with gdx_pixbuf in gtk2, and they work perfectly with
> > the same images. Why cannot the gimp do the same quality dithering if
> > it's using the same library?
> The GIMP display canvas uses the dithering routines from GdkRGB which
> is probably what you are refering to. Of course this does only affect
> the display, not the image data. I am not sure but I think I remember
> a plug-in that could apply dithering to RGB images w/o converting to
> Indexed colors.

Actually, gqview defaults to GDK_RGB_DITHER_NORMAL whereas gimp uses
GDK_RGB_DITHER_MAX always, which should theoretically do a better job.
Maybe you could put up a sample image somewhere so we can see what exactly
the problem is?

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