Color Mode in Affinity Photo and export to EXR

[Aardo]

I need some clarification on color modes available in Photo. Namely the RGB/16, is it integer or float and if float then how can I input colors below 0 or above 1? And then there is RGB/32 HDR, is it integer or float, and if float, how can I input colors below 0 and above 1? Also are these modes linear or gamma corrected?

Another thing is the export to Open EXR (when I choose More... options). I can choose from 16 bit half and 32 bit float, what is 16 bit half, is it integer or float?

One more thing: I have some HDR and EXR files, which I'm certain contain values above 1 (32-bit float), but Photo shows them as 1 (ie. 255 in each RGB channel in the Info panel). How to show the true value, if it's above 1 or below 0?

Edited April 17, 2019 by Aardo
one more question

[James Ritson]

Hi Aardo, welcome to the forums. Hopefully these answers will be OK for you:

RGB/16 is integer, we only support float in 32-bit. 16-bit and 8-bit are gamma corrected, whereas 32-bit is linear. By default, however, 32-bit uses an ICC display transform (i.e your monitor profile) for a non-linear transform to screen. You can configure this through View>Studio>32-bit Preview where you can choose between display transform, unmanaged (linear) and OpenColorIO transforms if you have a valid OCIO configuration set up.

To create colour values below 0 and above 1, you can double-click on the current colour within the Colour panel and it will open up a colour dialog. At the bottom you'll have 32-bit options including an Intensity slider and interactive dialog where you can add/reduce the values in intervals. You can also colour pick values from your document that are out of range. Additionally, if you click the circular icon where it says Opacity on the Colour panel (beneath the HSL wheel/colour sliders) it will cycle between Opacity, Noise and Intensity—the latter of which again allow you to create out of range values.

For OpenEXR export, both 32-bit and 16-bit options are float (or half-float as it were for 16-bit).

Regarding your HDR and EXR documents, I believe the Info panel is always constrained to 0-256 values. You should be able to colour pick out of range values (as mentioned above) however.

Bear in mind that there is a bug with the Windows version that clamps the colour picker and the colour dialog to 0-1. We're currently aware and this is being addressed for 1.7's release. If you're on macOS, everything will work as expected. The next Windows public beta of 1.7 (https://forum.affinity.serif.com/index.php?/forum/34-photo-beta-on-windows/) will hopefully fix the clamping issue.

Hope that helps!