Create Color Composite in Krita

Question

Can I create an RGB color composite in Krita?

In Krita I separated a color image into RGB bands using Separate Image function (equivalent to Decompose in Gimp).

Now I would like to put them back into RGB composite (like Gimp does Compose).

So far I looked into Image / Filter menus but could not find a likely tool. G'MIC plugin has Decompose Channels tool but I have not been successful using its Recompose option.

Answer 1

The canonical "no smart tools" way

I assume you have 3 greyscale layers Red, Green and Blue. I call them separation layers.

Create above your separation layers new paint layers which have just that color which is the name of the separation layer below. Let it have layer mode = Multiply

I have here a solid blue fill RGB=0,0,255 above my blue separation layer

Then merge the color fill layes with their separation layers and give to the bottom layer blending mode = Normal, the rest must have blending mode =Addition:

Finally merge all 3 color layers. Use Layer > Flatten image for this.