Following on the multilayer EXR thread I tried several single layer EXR.

When the EXR is created in a way where the single layer has RGBa channels, Krita is making funky stuff with the alpha:
- Splitting Layer's Alpha into Mask removes RGB info from layer and breaks the image;
- The same thing might be happening when tonemapping as the curves, levels, etc, filters also break the image;

EDIT: Here is the test file:

https://app.box.com/s/dxmmvrdnm5aal76krb3slh5toeoqal5a

Going to submit the bug.

Thanks for fixing multilayer EXR!

However I've noticed that EXR RGBa isn't yet fixed for single layered images.

I don't understand why this is behaving differently than what's supposed but I'm sharing 4 files in a folder:

https://app.box.com/s/ew5uo4vykxmu16tbu1l1s87llsypcc9f

FILE 1
"01 RGBa Test.exr" - The test file wich has 4 channels (RGB + Alpha) for you to import into Krita. The first thing you'll notice is, of course, the dialog below. The result is that background colors disappear. What I'd like for you to test is to split alpha on the existing layer by right clicking on it. RGB info is gone as soon as you split alpha.

Dialog:
https://app.box.com/s/03adxdb5zu54w8wmmln3okc7w5ybbjzp

FILE 2
"02 RGBa Test.png "- A test file for you to compare what is happening with another file with the same 4 channels (RGB + Alpha). Try the same thing: Import into Krita and split alpha like above. The result is what you'd expect. Transparency mask is created but the background colors are still there. RGB info isn't disturbed when you split alpha. This is what should happen with EXR too.

FILE 3
"03 RGBa Test EXR Its Importing Like This.kra" - This shows the result of the process described for FILE 1

FILE 4
"04 RGBa Test EXR Should Import Like this.kra" - This file shows what should happen when using the process from FILE 1

FILE 5
"05 RGBa Multilayer Alpha Test.exr" - Was created from the same renderer (Thea) but alpha channel was rendered along with other channels (Color, Alpha, Material ID, Reflection, Refraction, Shadow). It was then saved as a Multilayer EXR. In this file, alpha is being interpreted as a separated channel. This was the base file I used to produce "FILE 4". What I did was:
a) Import the multilayered EXR wich is now working flawlessly (Thanks!);
b) Converted Alpha channel into a transparency mask attached to the first layer (RGB);
c) Erased all other channels.

What I find interesting is that dialog that shows up saying that a colored pixel cannot have 0 alpha? Why is that? It is allowed with PNG as shown with "FILE 2", why can't the EXR in "FILE 1" behave the same?

I'll relate this post with the BUG I already posted. (I'm sorry if I did write it here first, but I thought it would be useful to share with other people that is used to EXR workflows...)

Thanks for all the attention and effort put into this.

Best regards,

João

BUG link:

https://bugs.kde.org/show_bug.cgi?id=352837