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Sounds official anyways..

Can ANYONE take one of the ACEScg Golden Images https://github.com/ampas/aces-dev/tree/master/images ( SonyF35.StillLife.exr ) and save it out from Photo as an sRGB JPG or TIFF and match the EXR as it's displayed in the OCIO Display Transform (It should also match the golden image reference 'SonyF35.StillLife_ODT.Academy.sRGB_100nits_dim.tiff') ?

Theoretically this should be a SIMPLE challenge and maybe I'm just dumb as a post and I'm missing the magic button right under my nose. If so, please put me out of my misery! :)

 

Travis

SonyF35.StillLife_ODT.Academy.sRGB_100nits_dim.jpg

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Hi @travisrogers, yes, managed it! (Albeit with some very minor differences when zoomed in and doing a quick A/B comparison)

When opened in Affinity Photo, the reference TIFF is being colour managed from sRGB to the display profile, so for this challenge I'm assuming this result is the correct one. I'm also using ICC Display Transform and not OCIO Display Transform with the 32-bit EXR.

You can append the colour space to the file name (e.g. "filename aces") and Photo will convert from that colour space to scene linear, but in practice with the file provided it made little to no difference.

The next step is to add an OCIO adjustment layer and go from scene linear to out_srgb (the pointer/friendly name for this is "Output - sRGB").

Finally, to match the look of the 16-bit TIFF, we need to add a simple gamma transform—this is because ICC Display Transform uses the display profile's non-linear transform to ensure parity with the results you'll get when you export to a non-linear image format like JPEG. A Levels adjustment isn't flexible enough here, so the easiest way to achieve this is to add a live Procedural Texture filter and do a power transform of 2.2 for each colour channel. I've attached a screen grab below to illustrate:

gamma_transform.png

And that should be it! I've attached a side-by-side comparison. This is the best match I've been able to achieve so far..

Comparison.jpg

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Oh James :4_joy:

Brilliant man! I believe this is the magic button I was looking for! I honestly would have never thought to use the procedural texture to modify gamma and couldn't figure out how to get around the Levels gamma limit of 2. Now I have a new tool to play with and am super happy to be using the wider gamut of ACES. I'm certain that the difference is due to moving from 32 to 8 bit, but otherwise the outcome is well within the acceptable range.

Thanks as well for putting together your workflow bundle. I'll say that both the bundle and the procedural texture gamma trick would be great quick tip videos for the community.

 

One quick question if you have the time. If you were working on an ACEScg file and you wanted to save it out to a wider gamut than sRGB for fine art printing. Would you output to Rec.2020 via an OCIO adjustment layer and then convert to something like Adobe RGB through Document Convert / Format (8 bit)? Or given that it's already a linear file, will setting the output to out_srgb allow you to convert to AdobeRGB and take advantage of that wider space?

I'm still getting my head around linear files and how they can be converted as traditionally if the image was in sRGB, you could convert it to AdobeRGB, but there would be no advantage as it wouldn't add any more color information.

 

Again, thanks for your help here, it's much appreciated! Challenge won!

Travis

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  • 5 months later...

hi james, i'd be happy to use your macro, as i'm new to affinity and don't know yet how to automate processes and this here would be a solution i was also looking for. the link appears to be broken though, any chance to have that re-uploaded? i'd be grateful! thx and keep up the good work!
ivan

Edited by grebenshyo
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  • 2 weeks later...

I'm very new to Affinity Photo but I would like to share this workflow.

I have a different solution that provides perfect results.

First I created a LUT that removes the sRGB gamma in Fusion Studio. I used with the create LUT tools and a Gamut node removing sRGB Gamma.

In Affinity I did the following;

  1. Set the display profile to Unmanaged.
  2. Added a OCIO adjustment layer with the setting set in my case...Source colour space ACES - ACEScg and Destination colour space Output Rec.709 (Should look identical to when viewing with the display profile set to OCIO and output Rec.709 and without the adjustment layer on)
  3. Added a LUT adjustment layer and imported the LUT created in Fusion. The image will appear now darker but when exported will be correct, as Affinity is adding back the sRGB curve.

I have attached the  LUT if interested.

There should be a better way to do this in Affinity Photo as PSD can do this without the LUT and has ICC profiles for working ACES and converting to the proper outputs. Hope there is a native solution soon ;-).

Tim

Remove_sRGB_LUT_.3dl

Edited by Bopstar
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  • 1 month later...

Hi @Strandbummler, if you use the LUT that I have made available along with the steps it will work perfectly for your needs.

You will need to be logged in to download the LUT.

The only thing you will most likely need to change is the OCIO Adjustment layers Destination colour space if REC.709 is not the desired or correct destination for you, most likely want to set that to sRGB as that is usually more common.

Anyway let me know how you go with this method, as I'm interested.

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  • 9 months later...

hi there to, all PS killers ;)

for me ACES workflow is soo nice, also AFphoto with exr from blender with aces ocio, works flawless

yes, gamma need to be added, I'm quite also happy with my approach,

curves adjustment with values for y=x^2.2 for gamma 2.2

see the file, feel free to use  😋 

gamma_curve.afphoto

while this might be off a little bit, for me it looks also good ^^ while Procedural Texture is more accurate

1852268488_2021-04-0914_15_31.thumb.png.2e2091b46326f2b4b4c1175f7e1645bf.png

 

1423784952_2021-04-0913_54_30.thumb.png.1465a559bbf519644041b0e875bc2c16.png

Edited by Sonicdee
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