Krita/Manual/Basic Concepts

Revision as of 16:44, 31 March 2015 by Raghukamath (Talk | contribs) (Blending Modes, Gimp, Photoshop and Krita)

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This manual is a rewrite of the 1.6 manual. It is not complete.

Basic Concepts

Krita is about painting, introduction to digital painting, layers, blending modes, links to fun stuff.

Blending Modes, Gimp, Photoshop and Krita

I think we can only maintain compatibility with other applications but not UI-consistency (or consistency in usability, or whatever). Right now we are trying to maintain compatibility with Gimp and Photoshop but these two applications really behave different when it comes down to compositing. For compositing Photoshop uses some kind of weighted average (or whatever) to mix the source color into the resulting color and recalculates the alpha value accordingly when the destination color is semitransparent but Photoshop does this only for compositing while painting. And you can disable this by locking the alpha channel in Photoshop. Gimp doesn't use this at all (besides the "Normal" blending mode). Gimp behaves for all blending modes expect "Normal" like if the alpha channel is locked.

And now we are here with Krita. Krita doesn't distinguish internally between compositing the brush strokes and layer composition (it uses the same code). To make it compatible to Photoshop we implemented the blending mode computations after the specs of Adobe. And since Krita doesn't distinguish between the two compositing types we only could bring this all together by adding the Disable alpha button so that the user can choose what he/she prefers.

To explain the behavior in short :

  • Inverting the alpha channel will alter the default behavior of the "Normal" blending mode (leads to incompatibility to both Gimp and Photoshop)
  • making it completely consistent to Gimp will destroy Photoshop consistency (and vice versa).

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