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toodee

Bug in Convert Format / Assign ICC Profile?

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Hi, 

I noticed a strange behavior with the release version of Affinity 1.7 that I don't recall with the last Beta versions (that I already deleted) and for sure not with the version 1.6.x.

I use the Serif RAW converter to convert canon raw photo files to 32-bit linear files.

When the prefs are set to 32-Bit sRGB linear, then after the raw conversion I convert the format to ACEScg.

When the prefs are set to 32-Bit ACEScg, then I don't need to do anything else after the raw conversion.

In both cases I export EXR (half-float files) without the check box "Color profile from name".

When I loaded both files in Nuke (from Foundry in an ACES environment with each the right colorspace settings) they were looking (nearly) identical. 

And this made sense to me.

I checked with older files EXR files (that were converted with an older version of Affinity Photo) and the two exports are visually identical. There are very small differences in the colors, this might be rounding errors. The linear sRGB file is actually ever so slightly warmer then the ACEScg file.

When I do this now with the new release of Affinity Photo, the ACEScg converted file got much warmer.

The two attached images (IMG_7330) were converted with version 1.7 Prefs 32-Bit sRGB linear, Serif Engine (no tone curve), the lin sRGB was then directly exported as EXR, the ACEScg was converted with Document/Convert Format/ICC Profile to ACEScg and then exported as EXR. Both files were exported with Nuke to JPG (with the same display viewer curve RRT&ODT)

The older files (IMG_8454) were converted with an older version of Affinity Photo (April 2017)

I can provide the .CR2 files if necessary. 

Can someone explain why this happens?

 

Best regards

 

 

Daniel

 

IMG_7330_RAW_lin_sRGB_Nuke_to_JPG.jpg

IMG_7330_RAW_acescg_Nuke_to_JPG.jpg

IMG_8454_ACEScg_Nuke_to_JPG.jpg

IMG_8454_lin_sRGB_Nuke_to_JPG.jpg

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Hi Daniel

I can reproduce this if I set the Rendering Intent in Colour Preferences to Absolute Colorimetric. Is that what you have set? If so, does it behave as it used to if you change to Relative Colorimetric?

Justin

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6 hours ago, Justin said:

Hi Daniel

I can reproduce this if I set the Rendering Intent in Colour Preferences to Absolute Colorimetric. Is that what you have set? If so, does it behave as it used to if you change to Relative Colorimetric?

Justin

Hi Justin,

thanks for your quick answer.

Yes indeed, on one of my two machines  the preference was set to Absolute C. and on the other to Relative C. I got no idea why this was set like this because I never touch these settings.

When it is set to Relative C. then it behaves like it used to be.

Thanks a lot for your help.

 

 

Daniel

 

 

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@toodee - A little off topic... I am not sure if you are aware, but the ACES working group has a command line utility called raw2aces that uses the libraw raw conversion library to convert supported raw files to ACES EXRs.  See:

https://acescentral.com/t/rawtoaces-calling-all-developer-types/1048

You can use a package manager or similar to build it.  I use homebrew to build the latest version on my mac.  Maybe helpful for you?  

kirk

 

 

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Hi kirk,

 

yes, I am aware of that tool. We tested it a while ago back, but we were not really happy with the results. And for single images, I prefer to see the image in a raw converter and can check out settings.

And as far as I remember it also kills all metadata from the raw images, so it makes it harder to use them in PTGui for example.

But its a good hint as I should check it out again.

Thanks

 

Daniel

 

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On 6/18/2019 at 1:51 AM, kirkt said:

@toodee - A little off topic... I am not sure if you are aware, but the ACES working group has a command line utility called raw2aces that uses the libraw raw conversion library to convert supported raw files to ACES EXRs.  See:

https://acescentral.com/t/rawtoaces-calling-all-developer-types/1048

You can use a package manager or similar to build it.  I use homebrew to build the latest version on my mac.  Maybe helpful for you?  

kirk

 

RAW2ACES sounds like a great idea, but there are not many cameras fully supported and its very nice in Affinity Photo to have a visual feedback to the settings you use before you finally develop the RAW image.

Sure, for a big number of RAW files the batch capabilities of Affinity Photo are still not that great.

 

Best

 

Daniel

 

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