Firstly, really nicely done. Very clear, and the interactive gradient explorer was excellent for quickly exploring the spaces. To understand the comparison it

Firstly, really nicely done. Very clear, and the interactive gradient explorer was excellent for quickly exploring the spaces. To understand the comparison it is critical to state what absolute luminance was used for media white in the ICtCp gradient. 80 100? 203? 10,000 (surely not)? The SDR to HDR mapping chosen has a big effect on the results for these HDR colorspaces using PQ or PQ-like transfer functions. That mapping also has a big effect on the comparative transfer function graph. I worry that the curve for ST2084 starts and ends at the same place the others do. Does that mean you mapped media white to full-scale, absolute maximum small-area peak white? I would have liked to see the arguments in favor of a single transfer function vs. a piecewise curve-plus-linear (or curve plus curve, in the case of HLG) expanded a bit more beyond computational efficiency and GPU-freindliness and more in the direction of correctness and fitness for purpose.