[Openicc] review of new wide gamut editing space

[Graeme Gill]

Chris Murphy wrote:
> If we go to 32bpc float as a minimum across the board, neither primaries nor TRC matter at all.
> Finally, peace.

It's still important to distinguish between editing and final delivery both in terms
of number representation and gamut. A 4 x increase in storage space and bandwidth
is still not trivial, even though some people would like to imagine that it can
be ignored. When rendered to a typical output gamut, 8 bits is still very satisfactory
for everyday use, particularly if the imagery has natural noise in it, while 16 bit is
total overkill. Even in editing, 16 bits exceeds the Signal to Noise ratio of any real sensor.
And then there is the gamut problem. With constrained values and real device profiles
you have a defined gamut. With unconstrained values and/or imaginary colorspaces you don't,
and you have to adopt a workflow that recognises that you can't assume source gamuts based
on the colorspace. Few people or systems do so.

Graeme Gill.