Please add support for HDR gain maps (at least JPG)

[Greg B]

Affinity has some great tools for editing HDR, but lacks critical support to import or share the work. It cannot import or export HDR gain maps in JPG, HEIC, or AVIF file formats.

The best way to export share HDR is via a "gain map", which allows the image to adapt to any display (regardless of level of HDR support). A JPG with a gain map is the ideal way to do that now (and AVIF with a gain map will be important in the next year).

And the native way that HDR images are captured on iPhone or Android now is via JPG or HEIC encoded with a gain map. These HDR images are not supported by Affinity (it shows only the SDR base image for JPG, and will not open HEIC at all).

The priority is encode / decode support for JPG and decode support for HEIC (at least under the ISO gain map spec). This would allow support for smart phone captures and sharing any images edited with Affinity. Support to decode other XMP gain map encodings would be nice for legacy support, but phones are already capturing with ISO encoding and this is not as critical. It would ultimately be ideal to have support for AVIF gain maps, as that will become an important standard in the near future.

Attached is a test image which should show blue HDR text when opened with proper HDR support. If the display supports 4 stops of HDR headroom, the text will be clear. If it less headroom, it will show the blue HDR very faintly (this is a good and expected result based on how the image is encoded).

HDR blue text_800x800_U_0_P3_Original ratio_gainMap.jpg.zip

[wgphoto]

On 2/5/2025 at 12:16 PM, Greg B said:

Affinity has some great tools for editing HDR, but lacks critical support to import or share the work. It cannot import or export HDR gain maps in JPG, HEIC, or AVIF file formats.

The best way to export share HDR is via a "gain map", which allows the image to adapt to any display (regardless of level of HDR support). A JPG with a gain map is the ideal way to do that now (and AVIF with a gain map will be important in the next year).

And the native way that HDR images are captured on iPhone or Android now is via JPG or HEIC encoded with a gain map. These HDR images are not supported by Affinity (it shows only the SDR base image for JPG, and will not open HEIC at all).

The priority is encode / decode support for JPG and decode support for HEIC (at least under the ISO gain map spec). This would allow support for smart phone captures and sharing any images edited with Affinity. Support to decode other XMP gain map encodings would be nice for legacy support, but phones are already capturing with ISO encoding and this is not as critical. It would ultimately be ideal to have support for AVIF gain maps, as that will become an important standard in the near future.

Attached is a test image which should show blue HDR text when opened with proper HDR support. If the display supports 4 stops of HDR headroom, the text will be clear. If it less headroom, it will show the blue HDR very faintly (this is a good and expected result based on how the image is encoded).

HDR blue text_800x800_U_0_P3_Original ratio_gainMap.jpg.zip 73.23 kB · 0 downloads

+1, please listen to Greg on this. He knows his stuff with HDR exports, etc. As an avid Affinity user since 2015, I’d love to be able to use AP for HDR exports that will adapt to a viewer's display/app capabilities. Thanks Greg for getting the ball rolling.

[Ldina]

+1,000,000!!! HDR using Gain Maps is the future (and already supported by Adobe). Gain Map creation and support needs to work with standard JPG, AVIF, JPEG-XL and HEIC. 

[dancole]

+1. I've been trying out affinity, and overall it seems pretty good for viewing and editing HDR, but being unable to export gain map's means that nobody can ever view or see these images properly. JPEG and AVIF gain map support would be amazing.

[karipu]

HDR gain map: yes, please and asap!

[Petar Petrenko]

On 2/18/2025 at 11:38 PM, Ldina said:

Gain Map creation and support needs to work with standard JPG, AVIF, JPEG-XL and HEIC.

JPEG-XL is not completely supported in Affinity. It exports only flatten image, not with layers.