Alright that makes sense.
Though that space (are we talking about scRGB?) works well for alpha compositing, values outside the [0,1] range will cause unexpected behaviors with other type of compositing operations. For example, operations that multiply or divide color components with other color components may behave in unexpected ways.
Anyways… The more important issue here is that there needs to be a guarantee that the color space used for compositing be an adequate intermediate. We discussed this in the Khronos thread and we agreed that the exact color space used for compositing is up to the implementatation but it must satisfy the requirement that using the space as an intermediate between the canvas’s color space and the display’s profile most not cause any undue banding or gamut clamping. I forgot to capture that in the proposal. I’ll fix it.
Thanks for spotting that! Let’s follow what WebGL does.