Jump to content
You must now use your email address to sign in [click for more info] ×

Processing files in Affinity Photo for best quality output on HDR/EDR displays. Suggestions?


Recommended Posts

I recently acquired a 16" M1 Macbook Pro, with Apple's "Liquid Retina XDR" display and mini-LED backlight. Viewing 4K HDR YouTube videos is a treat. The results are stunning - closer to the brightness and contrast range of real scenes than any computer screen I've seen. I don't do much with video, so this got me wondering. Could I use Affinity Photo to obtain a presentation of my photos, on HDR emissive devices, with a similar extended dynamic range?

I watched Affinity's tutorial videos on HDR/EDR workflows, and reviewed other materials in Apple user and developer resources. I did not find much guidance on best practices for processing static photos. In an earlier message in this forum, James Ritson mentioned that there is currently no suitable image format for these files. Here is a description of what I am currently trying, and the limitations I encounter. Perhaps someone can offer suggestions on a better workflow.

My starting point is usually a single raw file from a Nikon D850. When there are significant specular reflections or emissive light sources in the scene, I underexpose to minimize clipping. The Mac and Affinity Photo are configured as follows:

macOS 12.1 Monterey

System Preferences  > Display > Presets = Apple XDR Display (P3-1600 nits) or HDR Video (P3-ST 2084)

Affinity Photo 1.10.4

Preferences > RGB Color Profile = Display P3 [probaby irrrelevant]

Preferences > 32 bit RGB Color Profile = Display P3 (linear)

Preferences > Rendering Intent = Relative Colorimetric, with BPC

Preferences > Enable EDR by default in 32 bit RGB views = YES

Develop Assistant > RAW Engine = Serif Labs

Develop Assistant > RAW output format = RGB (32 bit HDR)

Develop Assistant > Tone curve = Take no action

32-bit Preview > Enable EDR = YES

All other settings are at defaults. After loading a raw file, I adjust exposure, clarity, saturation, etc., while monitoring and minimizing EDR clipping. Then I move from Develop to Photo persona and export a file in OpenEXR 32-bit linear format (.exr).

The .exr files are readable by several of the Mac apps that I have, but most of these apps do not display the images correctly. When viewed in Affinity Photo, EDR is activated, and my edit adjustments are respected. Apple's Preview app displays the files in EDR, and the appearance is very close to what I see in Affinity Photo, but with a slight loss of saturation. Why is that?

On my Macbook Pro's mini-LED screen, and with a compatible app, the .exr files look terrific, but only if Display Preferences are configured for the same preset and brightness that was used for editing. With the wrong app, or the wrong display preset, the image can be a dull washed-out mess.

I tried exporting the files in TIFF RGB 32-bit, but I don't have any apps other than Affinity that can read that format correctly.

While we are waiting for this technology to mature and standardize, I would still like to make HDR versions from some of my photos - for my own enjoyment, and to torture my friends with vacation slideshows. Apple'e Preview can run a full screen slideshow in EDR, albeit with the saturation loss noted earlier. I have not found out how to do this in Affinity Photo. Do you have any plans to add a slideshow feature? Do you know of any other Mac apps that can do it with EDR support?

Thanks to the Affinity boffins for giving us a headstart in this eye-popping HDR image display tech.

Link to comment
Share on other sites

  • Staff

Hi @julianv, unfortunately I believe your saturation issue does come down to the issue that I brought up in a previous post: lack of a decent delivery method for HDR/EDR images with appropriate metadata. The formats are kind of half-there, but OS level support needs to mature significantly.

EXR documents are a way of interchanging lossless information and allow unbounded, floating point precision for pixel values, making them ideal for storing HDR content but not particularly for visualising it. EXR files have no real concept of colour space, and are not tagged with colour profiles. The pixel values are usually encoded as linear scene-referred values, as opposed to gamma-corrected values in a particular colour space. This is why colour management solutions like OpenColorIO are typically employed when dealing with EXR files, to ensure accurate colour conversions between the linear values and the intended output space.

I'm not sure what macOS does with its EXR integration—I'm assuming it would just convert from the linear values to sRGB in order to preview on-screen, which may explain the loss in colour intensity because you are working with the Display P3 profile within Affinity Photo.

As a quick experiment, you could try using Document>Flatten, then Document>Convert Format / ICC Profile and choosing sRGB (stay in RGB/32 for the actual format). Now export your EXR and see if the result in Finder/Preview looks more consistent with what you are seeing in Affinity Photo. If so, it is unfortunately a limitation where you cannot mandate a colour profile for your exported EXR document—for now, the only real workaround would be converting to sRGB before exporting.

Hope that helps!

Product Expert (Affinity Photo) & Product Expert Team Leader

@JamesR_Affinity for tutorial sneak peeks and more
Official Affinity Photo tutorials

Link to comment
Share on other sites

Thanks for the reply, James. I tried the experiment that you suggested, and indeed the exported EXR file in Apple Preview looks identical to an sRGB version in Affinity Photo. So your theory is probably correct: Preview does not know what color space to use for an EXR file, so it defaults to sRGB. My EXR files look great and display with full saturation when opened in Affinity Photo. At least, that's what happens if AP is configured to use Display P3 (linear) as its working space, which is what I used when converting the original raw files. But I have not found any app which can run a full screen slide show of EXR files loaded into that color space, and with EDR enabled.

As an interim solution (while waiting for better EXR support in macOS), would I get any benefit from using OpenColorIO color management? I watched your video tutorial on OpenColorIO setup. If this workflow might be useful, how would I choose an appropriate config.ocio file, and how would I set up the device and view transforms?

Link to comment
Share on other sites

  • Staff
On 1/21/2022 at 1:00 AM, julianv said:

As an interim solution (while waiting for better EXR support in macOS), would I get any benefit from using OpenColorIO color management? I watched your video tutorial on OpenColorIO setup. If this workflow might be useful, how would I choose an appropriate config.ocio file, and how would I set up the device and view transforms?

Hey again. I wouldn't go anywhere near OpenColorIO to be honest, that's more intended for a VFX/rendering pipeline. The OpenColorIO view transform in Affinity Photo is non-destructive anyway, and will not match the view you get from EXR previews in Finder or other macOS software that can interpret the format. I'm afraid there is no elegant solution at the moment!

Product Expert (Affinity Photo) & Product Expert Team Leader

@JamesR_Affinity for tutorial sneak peeks and more
Official Affinity Photo tutorials

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Terms of Use | Privacy Policy | Guidelines | We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.