RGB 16 bit as default when starting Krita

Boudewijn Rempt boud at valdyas.org
Wed Jan 20 15:02:25 CET 2010


On Wednesday 20 January 2010, Cyrille Berger wrote:
> Hello,
> 
> On IRC, I was suggesting that Krita start to using RGB 16bits as a default
> when creating images. I don't think there is a good reason to create 8bits
> image files nowdays. Of course, when you open an exisiting 8bits image,
> krita would still open it as 8bits. Despite most display being limited to
> 6-8bits display, when drawing, 16bits reduce most of the errors due to
> limited 8bits range.

I think we should give it a try, for instance during the 2.2 beta period. We 
would need to very carefully measure the performance hit, though. For 
instance, we'd have a conversion hit we don't necessarily have for rgb8 for 
display, and there's the issue of the opengl canvas that needs to be measured.

Also, memory consumption will double unless we implement tile compression.

> This also raise the discussion of wether to use sRGB (2.2 gamma) or scRGB
> (linear in light) profile.
> 
> In favor of sRGB:
> * when saving to PNG or JPEG, krita embedd the color profile, but, most
> 
> In favor of scRGB:
> * Fix a lot of gamma imperfection, for instance like scaling:
> http://4p8.com/eric.brasseur/gamma.html

I think Maxy tried this and found that linear light gave unintuitive results 
when painting, so we should test this

> An alternative could be to use scRGB in Krita, and then to add a "convert
> to sRGB" option in png, jpeg and tiff that would be checked by default.

Yes, that would be a good option.

-- 
Boudewijn Rempt | http://www.valdyas.org


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