Re: how to invert greyscale values only... leaving colors alone

[Sven Neumann <sven@xxxxxxxx>]

On Mon, 2010-02-01 at 15:27 -0800, Rich Evans wrote:
> Hello, Is this the right place to ask a question about special filters in GIMP? If so, I'd love some advice on the following task:
> 
> I have an RGB image that is basically a black background with many
> colorful objects and white text.  --- I'd like to invert the image so
> that it is a white background with black text but a simple invert
> inverts the colors in all the colored objects as well. Is there a
> technique or tool to invert any part of the image that is only a shade
> of grey? i.e. invert pixeils with a saturation of ~0 (if that is how
> you say it). I could imagine a filter that does a simple RGB invert
> for any pixel whose calculated RGB saturation value is below a set
> threshold. Does this type of tool/script exist?

Simple. First create a duplicate of your layer. Then invert the colors
on the lower layer and set the layer mode of the upper (unchanged) layer
to "Colors".


Sven


_______________________________________________
Gimp-user mailing list
Gimp-user@xxxxxxxxxxxxxxxxxxxxxx
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user