[Gimp-user] why would the input png automatically get blurred?

[bsmile <forums gimpusers com>]

> In indexed mode, the color of a pixel in the image (in all layers) is 
> taken from a "color map". Since the index in the color map is a 8-bit 
> byte, you can only have 256 colors (across all layers). When you
> import
> another image, its colors are approximated with the 256 colors in the 
> current colormap. The first victims of this color shortage are the 
> anti-aliasing pixels along the edges of things that are a blend of the
> two colors in various (and numerous) proportions(*) and the edges
> become
> jagged.
>
> (*) Experiment: Take a blank image, add a black text layer, and merge
> it
> down to obtain one single layer with black text over white. Then Go to
> Colors>Info>Color cubes analysis.  You will find much more than two 
> colors... these are the 250 shades of grays used in the edge pixels.
> You
> can start Color>Posterize and see what happend to the text outline
> when
> you reduce the number of colors.

Thanks, yes, I did the experiment and I saw the change now.

-- 
bsmile (via www.gimpusers.com/forums)