Affinity Photo unable to replicate photoshop brush stroke.

[polymath]

Hello, I am a long time user of Photoshop and also purchased Affinity Photo and Designer. My original intention was to replace photoshop but I'll show you a big dealbreaker for me that still keeps me on photoshop for digital painting. Simply put, the alpha of a single brush stroke should not MIX with itself. It should instead REPLACE what ever alpha has already been painted during that stroke. Best way to describe this annoyance is in the screenshot i've prepared below where i tried to replicate a standard hard brush in affinity Photo as best i can and do the same brush stroke in PS and Affinity Photo. As you can see, the alpha of the brush stroke is mixed instead of replaced which creates these undesirable dark edges lines.... This appears to be hard coded into the engine...

 

 

[Lee D]

@polymath Sorry for the delay, I can confirm this is part of how the brush engine works. You can post in the Feature Requests section as a future improvement but I suspect it would require a complete rewrite of the brush engine.

[Jose3DSigner]

Thanks @Lee D

Current brush overlapping method is good for simulating a felt pen or an airbrush but, as @polymath said, alpha replacement method is necessary for getting more accurate digital shadings, based on pen pressure. 

A well conceived brush engine should allow the combination of both methods in order to simulate almost any tool, I mean, a color blending mode like mix, add, multiply, lighten, colorize, etc. and, separately, an alpha blending mode like add (current Affinity Photo default method), replace, replace if higher, etc. The alpha blend mode can easily be added to the current mode list as "replace highest alpha", "most opaque" ("replace" can be included as well, for more flexibility). The brush engine does not require to be completely rewritten, only one or two lines of code (for the bit comparison) would be inserted where the tip shape is added to the stroke.

Note that this issue/inconvenient was related here, as well: 

Anyway, I hope this is solved soon.