Separating image into four primary colors

[Flotsam2000]

Hi there,

Does anyone know how I would go about turning an image into just it’s four primary colors (and black), and then saving each of those colors as it’s own layer/png? Is there a plug-in that does this for you? I am trying to make multi color stencils....

[denzjos]

Maybe you can use the GMicQt plugin : Colors / Decompose Channels and set the color base to CMYK and the action to Decompose. 
Color the different results with CMY :
   

[rich2005]

@Flotsom2000

Primary colours ? Is this RGB or CMY or both + Black (K in cmyk)

It is possible using Gimp Colors -> Components -> Decompose and a bit of image manipulation.

A little more specific please.

[denzjos]

Found a plugin that may be a better solution : https://e-smog.org/blog/gimp/2018/10/10/...-10-6.html

   

[Flotsam2000]

(08-29-2020, 07:55 AM)rich2005 Wrote: @Flotsom2000

Primary colours ? Is this RGB or CMY or both + Black (K in cmyk)

It is possible using Gimp Colors -> Components -> Decompose and a bit of image manipulation.

A little more specific please.

Maybe "primary colors" is too broad. I just want to be able to separate any image into four main colors aside from black, so five colors... In order to save each color as a layer to export as a PNG so that I can create stencils from each of the five colors so that when stacked they compose the image again... Does that make sense?

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(08-29-2020, 08:26 AM)denzjos Wrote: Found a plugin that may be a better solution : https://e-smog.org/blog/gimp/2018/10/10/...-10-6.html

Hmmm. What does the plugin do? I can't read German 

[rich2005]

First the plugin. It is separate+ A very old plugin to create CMYK images suitable to send to a printing company. It does make layers of C,M,Y,K Last time I tried it in Gimp 2.10 (I see you are visiting from the future and using Gimp 3 ) It was very flakey.

Quote:.. I just want to be able to separate any image into four main colors aside from black, so five colors... In order to save each color as a layer to export as a PNG so that I can create stencils from each of the five colors so that when stacked they compose the image again...

Yes makes sense, but who determines the colours and If not the primaries RGB / CMY then you need to remember the colours used, each will be a mix of RGB.

Another question. You mention stencils, Are these hand-cut or something else, say masks used for screen printing ?

[rich2005]

First thoughts: Using this script: http://chiselapp.com/user/saulgoode/repo...-decompose

The image does not have to be indexed, but you do need some way of reducing the number of colours down to your requirement.

example: https://i.imgur.com/EwzTZ2O.mp4

[denzjos]

Rich, nice plugin find and good tutorial, I used it on my photo and this is the result (poor colors, but maybe this is what Flotsam2000 is looking for): 

   

[Krikor]

increasingly difficult to find scripts compatible with gimp 2.10

  GIMP Warning
'Indexed Decompose' plug-in left image undo in inconsistent state, closing open undo groups.

  GIMP Error
Execution error for 'Indexed Decompose':
Error: (: 1) eval: unbound variable: NO-DITHER

[rich2005]

Quote:...increasingly difficult to find scripts compatible with gimp 2.10...

As Ofnuts said in another post, it is probably the way the latest samj's portable Gimp 2.10 is compiled.