[magick-users] Abutting two images can change their colour

[Damien Dunlop]

> | By merely placing two images side-by-side the colour changed!
> | 
> | How come?
> | 
> I tested your two test images using the latest version and the
> color of 'A' does not change!

Good news! I have lots of images that need re-doing because
of this problem.

Can you identify `the latest version' binary for MS Windows?

I am using 6.4.2 06/27/08 Q16 which is quite recent.

> | Note that although this command specifies single-colour 
> | horizonatal slices, the result contains some `foreign' pixels 
> | within some slices?????.
> | 

> This should have only happened because 'dither' was replacing colors,
> when it should have been finding that the color present matched
> the color pallette and should not need dithering.

a) The convert command was itself creating the palette
of < 256 colours, so dithering should not have been
invoked. I now wonder if there is a way of specifying
a palette for convert, eg from a palette file. Will
have another look at the options.

b) Given that `dither' implies incremental random changes
about some mean, it seems strange that some horizontal
slices seemed to include only a couple of `foreign' colours.

BUT, maybe the entire slice WAS dithered and because
the changes were small, I only noticed the `outliers'.
Will have another look.