Re: Humans (and cameras and scanners) do not have a color gamut (?)
Re: Humans (and cameras and scanners) do not have a color gamut (?)
- Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?)
- From: WAYNE BRETL via colorsync-users <email@hidden>
- Date: Thu, 9 Jan 2020 08:33:38 -0700 (MST)
- Importance: Medium
"The conventional definition is that...input devices have no colors that they
(somehow) can't produce an output for."
I would say that input devices have no *spectra* that they (somehow) can't
produce an output for (the output may just be zero in any or all three
channels, of course).
I think if we're careful about this, we have to say that the input is not a
color, and neither is the output, until it is translated into a color
representation.
> On January 8, 2020 at 5:24 PM Graeme Gill via colorsync-users
> <email@hidden> wrote:
>
>
> WAYNE BRETL via colorsync-users wrote:
>
> > Summary: while I agree that sensors do not have a color gamut, they do have
> > a signal
> > gamut, which inevitably gets translated into a color gamut in any useful
> > system.
>
> That's the bottom line - it comes down to how you define "gamut" in the
> context of a color transducer.
>
> The conventional definition is that output devices will have colors that
> they are unable to reproduce, while input devices have no colors that
> they (somehow) can't produce an output for.
>
> A more generalist definition might be based on accuracy. A conventional
> output device becomes progressively more inaccurate as it is asked to
> output colors beyond its gamut. An input device typically has colors
> that it captures inaccurately due to different spectral sensitivities
> to a human observer. The latter can't be characterized by a simple
> clipping boundary, but if you impose a requirement for a certain
> tolerance of color accuracy, then the spectral gamut that an input
> device is useful over will be limited.
>
> Note though that a spectral gamut will have no directly corresponding
> tri-stimulus gamut, due to the many to one nature of such a conversion.
> i.e. for a particular color sensor you may have an example of a spectrum
> that it cannot accurately capture, which to a human is a particular color,
> but it's probable that there is a different spectrum that appears to be the
> same color to a human, that the sensor will capture accurately.
> (i.e. it's likely that the 3 dimensional sub-planes of the human
> and sensor in spectral space, intersect somewhere.)
>
> By definition humans have no color gamut limitations - anything
> we can't perceive, is not a color!
>
> We certainly have a spectral gamut - we only perceive 3 dimensions
> out of the possible spectral gamut, and our wavelength range is limited.
>
> Cheers,
> Graeme Gill.
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