Humans (and cameras and scanners) do not have a color gamut (?)
Humans (and cameras and scanners) do not have a color gamut (?)
- Subject: Humans (and cameras and scanners) do not have a color gamut (?)
- From: WAYNE BRETL via colorsync-users <email@hidden>
- Date: Tue, 7 Jan 2020 13:51:10 -0700 (MST)
- Importance: Medium
(changing the subject now that the seemingly interminable is seemingly
terminated) :>)
Could you (and/or others) expand on this statement?
"Humans (and cameras and scanners) do not have a color gamut."
Is it a way of saying that the raw output of a sensor (eyeball or other) is a
triplet of numbers that has no inherent meaning until interpreted as a color
(in the human visual system) or as a color to be reproduced (in a color
reproduction system)?
Plus, I would appreciate comments on the following:
If the human eye or other sensor is presented with a series of narrower and
narrower bandwidthe spectra, the color interpreted from the output will have
higher and higher saturation until (possibly) a point is reached where one or
two of the channel outputs goes essentially to zero; at this point, a limit of
the gamut of the reported triplets and therefore a limit of the gamut of the
interpreted colors will be reached. If one channel is zero, this triplet or
color will lie on a straight line portion of the channel ratio/chromaticity
chart - e.g., the straight line portion of a chromaticity chart between red and
yellow-green in the case of the human eye. If two of the channels go to zero,
the triplet ratio/chromaticity goes to a fixed point. (The latter never happens
for the human eye because of the wideband nature of the M and L cone
sensitivities, but it is a definite feature of the spectral sensitivities of
most or all color film and many digital cameras.) In the case of color film
with narrow sensitivities such that red and blue channels do not overlap, the
limits become straight lines from red to green and blue to green, with a point
limit for any spectra that excite only the green channel.
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