Need help with 32-bit .exr renders

[onyspot]

Hello, I had the chance to test Affinity Photo and it looks promising. I need it mainly for post production of 32-bit full float .exr renders which Photoshop cannot handle.

I am having a slight issue with how AP is displaying the renders that are saved from the render frame buffer. If I import an .exr into AP from the frame buffer using the automatic gamma settings (1.0) the image is not displayed correctly in AP,  the gamma is incorrect resulting in a very dark image. The imported .exr has an sRGB IEC61966-2.1 Linear profile attached to it. However if I set to Unmanaged in 32-bit Preview window and set the gamma to 2.2 I get exactly the same image as I see in the render frame buffer - which is what I want to work with since the render frame buffer will also export the same image as .png, .tiff, etc. However I cannot export an "unmanaged" image as a .png from AP since it will always export the image with ICC Display transform set to 1.0 gamma. How do I get around this? 

Working with the ICC Display transform image and playing around the gamma adjustment layer I can never get the same image I had in the render frame buffer. 

My next question is with regards to LUT's. I get very different results if I apply the same LUT in AP or the render frame buffer. The frame buffer will apply the LUT correctly, exactly the same as After Effects however AP gives a completely different result which doesn't look right. Any thoughts on why is this happening?

I am not really an expert on the subject of color management so it's possible that my workflow is incorrect however I do need to post edit and be able to save the image that I am seeing as the Unmanaged  2.2 gamma preview otherwise there would be no point of using the app for my renders.

Thanks for the help.

[v_kyr]

See this related thread ...

 

[onyspot]

Thanks for replying v_kyr but could you be a bit more specific? I am still trying to wrap my head around the topic. 

[v_kyr]

I don't do 32-bit .exr renderer stuff, but somehow remembered this older above referenced thread which deals with that thematic and thought it might can be useful for you reading across that. Further they also mentioned gamma setting problems there, one poster told ...

Quote

...I do gamma correction with imagemagick or Photoshop and then work with Affinity photo. OR I load the file in Photoshop, save it as 32bit and then open that in Affinity Photo. Then you can do all the editing you want in linear space (while actually seeing it gamma corrected for your monitor ) and save it back. But you do have a 32 bit file. If you ever want to go back to a linear 16bit file you'd have to use Photoshop or something else again. ...

I assume you already looked these here (?) ...

OpenEXR/32-bit

• OpenEXR Multichannel Import/Export
• OpenEXR Import Options
• Editing 32-bit 3D Renders
• OpenEXR: Using Alpha Channels & Association

[onyspot]

I've read multiple topics but never found a clear solution. The thing is I do not want to gamma correct my .exr because even if I try to match it to my render frame buffer image, the tones are different (second image where I applied Levels adjustment layer) and so are the LUT's (because they are applied to an initially different gamma?) which then messes up the colors, shadows, etc.. It can't be seen well in the cropped photo but essentially the whole lighting changes. In some cases it wouldn't make any sense to spend all this time perfecting materials and lighting like I see them in my frame buffer to then have to do it all over again with post processing after using gamma correction because an app doesn't display it (or save it) the same way it is displayed in the frame buffer.

 

The first image shows what I was talking about in my first post. You can see the unmanaged one being displayed exactly like the render. 

 

 

[v_kyr]

I see, maybe you should file in a request so that the dev team then reviews these issues and hopefully can fix it.

[lepr]

.

[Frank Jonen]

What profile is your render buffer set to? Rec709? sRGB? sRGBf?

In regards to using LUTs: Using a LUT in linear space without an additional shaper will result in an incorrect rendering (it will work, but not look as intended). Normally in an OCIO transform you set the colour space before the LUT gets applied, this creates a shaper. Affinity does not have that. You'd have to emulate one using a curves adjustment layer.

Rest assured, we all have the same problem of Affinity ignoring the OCIO transforms and simply applying the set 32-bit ICC profile. It's a pain, but the only way to remedy it is to mess with OCIO transform layers while looking at the image through an ICC profile until it looks right. 

Your best bet is to do the colour transforms before you bring the image into Affinity. Look into Affinity's 32-bit profile list in the settings, transform to that prior and you should be fine. Also disable the automatic transformations in Affinity's settings. IMO that does more harm than good (it's too easily overlooked). If it looks wrong when you open a file, you can assign the correct profile (or nearest) and know what is happening. It would be nicer to have that profile list as a drop-down meny right on the imported image layer, but keep in mind: This is not a compositing tool, it's a general purpose image editor. What makes life easier for us may well cause a WTF? Bingo session for the median user.

[onyspot]

Thanks for all the replies. After further testing this seems to be a render engine specific problem and not something related to Affinity.