Affinity equivalent of "Blend RGB Colors Using Gamma 1"?

[Medical Officer Bones]

Does anyone know if there's an option in both Designer and Photo to paint using a linear gamma? In Photoshop a handy "Blend RGB Colors Using Gamma: 1" exists in the Color Settings. It fixes the ugly non-linear blending while painting.

[Dan C]

Hi Medical Officer Bones,

Unfortunately we don't currently have a direct setting for this, however if you change your document to a 32bit HDR colour format then Affinity will use the linear nature of the colour profile and display colour blends as though this option were enabled. I hope this helps!
 

[Medical Officer Bones]

In Krita this is solved by using one fo the sRGB-elle colour profiles when creating a new document. I copied these profiles to Affinity Designer's ICC folder, and they do show up, but when I select them in the new document dialog, the blending is still non-linear (UGLY!).

But that motivated me to try the wscRGB profile, and now it blends in linear space.

 

But it still doesn't explain why the linear elle profiles wouldn't work in Affinity. Ah well, got it to work now.

[Medical Officer Bones]

Unfortunately, after some testing I've come to the conclusion that it's not very workable: black and white soft brushes create ugly banding/dithering. This has to do with white/light greys becoming more powerful in linear colour space, and Affinity doesn't calculate nice transitions when working in wscRGB colour space and 8bit colour mode. In short, it is unusable.

I checked this in PhotoLine and Photoshop too, and the black and white blending when using a linear colour profile is pretty bad in those two as well. In Photoshop it is possible to turn off the linear blending while painting with black and white, though, while in PhotoLine it is easy to assign a non-linear profile to each individual layer if necessary, so it can be solved in those. Not in Affinity, though. And compared to both Photoshop and PhotoLine, Affinity's blending between white and black is arguably the worst.

Krita, on the other hand, has no such issues. Just choose the -elle-linear sRGB profile to work in, and blending works fine, both for colours as well as black and white.

When I installed Krita's sRGB-elle-V2-g10.icc system wide in Windows 10, it became available to PhotoLine in 8bpc mode too, and worked just as good as in Krita. Although white is still very powerful: nature of the beast when working in linear. But Affinity resolutely refused to allow me to work with that profile with 8bpc images: that profile only becomes available when selecting the 32bpc RGB mode. Very frustrating.

Photoshop also allowed me to pick the same linear sRGB profile.

In Affinity's case the answer would be to work directly in 32bpc, which is a tad disappointing. That said, best quality is to be had in 32bpc mode.

A secondary issue with using the *wscRGB colour profile in Affinity: all the colour palettes become linear too, which is unwanted behaviour. It means it becomes quite awkward to select the colour you want, since the grey/white range is displayed in linear, throwing things off (midgrey in linear is waaay lower!). This also occurs in Photoshop when I selected the linear elle sRGB profile. Both Krita and PhotoLine compensate and keep the colour palettes visually sRGB 2.2, so picking colours is much more intuitive, with no change to the overall workflow.

Anyway, it's not that important. But still interesting to compare the various applications and their behaviour in marginal cases like these.

My takeaway here is that Affinity's colour management is somehow more limited in its implementation compared to the other applications I tested here, if the user is required or wishes to work with linear colour profiles in 8bpc or 16bpc mode. It would be preferable if the Affinity developers would improve this in a future version.

And it is also obvious to me now that the developers behind Photoshop's colour management chose the "easy" way out by implementing that specific colour setting which I asked about in the original post here. But hey, it works.

[Dan C]

I appreciate your in-depth testing and feedback to us, I'll have this thread moved to Feature Requests for our developers to see and either comment on or consider for a future update.