Is there a practical significance in wide gamut colorspaces?

Started Jan 30, 2014 | Discussions thread
Iliah Borg Forum Pro • Posts: 27,405
Re: Cameras and scanners do not have colour gamuts?

I think a lot of the controversy has to do with the definitions rather than the substance involved.

Not in this case. It is not definitions but misunderstanding of the subject. Somehow the registration error and the range of reproducible colours are getting mixed. Gamut is about reproduction, not registration. Camera is not reproducing colour, it registers colour, by means of measurement. Somehow a measurement tool (camera, limited only by the range of input brightnesses, about the same as a voltmeter is limited with the range of input voltage it can measure) is getting the properties of the presentation (reproduction, rendering, output) device. Camera registers all the colours that are present in the scene if they are within the brightness range.

To say a sensor has some RGB filters is a huge stretch, since in some cameras green is closer to yellow, red allows blue, blue allows red, and green allows all. It is not useful to think about camera filters in RGBG, RGB, RGBE, or some other term like that. Those are just common names, to simplify explanations and to avoid giving out the spectral characteristics of the filters. But even in common language words like "red" do not determine colour, instead they are determining a class of colours.

Those camera "RGB" do not form a cartesian coordinate system even when we do not account for noise and metamerism or metameric error. To define any operation on the space one needs first to define the space; which can be done by an appropriate colour transform. This colour transform is necessary an approximation, and most of the cases a rather crude one. Multiple colour transforms are possible, and they may be equally good "by numbers". It is that colour transform selected by somebody (or, maybe, the photographer himself) which defines the appearance (given it is not shrunk further by the output colour transforms).

So we are talking about a raw converter output and trying to define camera's "gamut of reproducible colors" looking at that output. No such thing, or, in colour terms, a red herring.

input device like a camera can record incoming photon counts in three broad but distinct frequency bands

Not distinct. Hugely overlapping.

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