# Spectral sensitivity

I am learning about light and color formation but I don't understand how does the sensitivity affects an image. Take for instance the different sensitivities for two "cameras" for each RGB channel

Would it be ok to say that camera one (blue plot) for each of the RGB sensors the brightness for colors around RGB is mostly uniform. Whereas for camera two (red plot) the brightness is concentrated only in a very short range in the RGB colors?

Is there more information (or probably I'm misinterpreting the graphs) that can be drawn from the plot? What would be the effects on an image?

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What are the two axes? Wavelength and some measure of sensitivity? –  MikeW Sep 29 at 0:57
Seems odd (and undesirable) that a sensor would have 0 sensitivity to certain wavelengths, e.g. 600nm, if that's how to read the red plot –  MikeW Sep 29 at 0:59
Relevant on another level: xkcd.com/833 –  Bart Arondson Sep 29 at 2:31
Yes x-axis is wavelength and the other is a measure of sensitivity. @MikeW I know is somehow odd but is only for learning purposes :) –  BRabbit27 Sep 29 at 7:19

The subject is much more complex than the following "simplistic layman's answer"** , but ...

Simplistically, a sample of light at a point can be represented by a two dimensional position plus an amplitude, or by the amplitude of three orthogonal component vectors. It is traditional to use Red Green and Blue, approximately corresponding to the colour receptor wavelengths in most human eyes* but other component vectors could equally be used. (* Some eyes lack all or some sensitivity in one or more receptors and it is claimed by some that a few people have an additional wavelength receptor).

The "red" curve set lacks sensitivity on some areas - overall light measured would be less than the total.

The "blue" curve set overlaps very significantly. Light at a wavelength midway between the Red (right hand) and Blue (middle) pek response points would appear equally in both red and green channels and could not be distinguished in any one channel from monochromatic light of a slightly lower intensity.

I would expect that the narrow red curves would have some issues with low sensitivity and not dealing well with some light with distinct spectra peaks BUT
I would expect the wide blue curves to provide a munged pastel colour inaccurate mess.

Of the two I would expect the narrow curves to do better, but better still would be something with broader squarer non overlapping response curves which have both very little dead space and minimal overlap. Non-existeum selective interference filters would probably meet the need.

Many idea starters and examples here

What real people typically claim From here

BUT there are many variations depending on application. One "trick" is to use sharp squarush non overlapping filters plus a luminance channel that covers the whole spectrum.

A few other examples.

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