The bayer filter allows for the passage of RGB light which is then recorded via photodiodes. However, since a bayer filter is more or less a juxtaposition(cetainly not literally a juxtaposition) of three optical filters, one for each R, G and B, thus there must be a certain specific peak wavelength for all the three R, G, and B, with a certain band being allowed to pass through around that peak wavelength. What is that peak wavelength for all the three colors?


2 Answers 2


thus there must be a certain specific peak wavelength for all the three

Not it must not.

1) The spectral sensitivities may have two or more extremums with IR filter removed.

2) Colorimetry does not require the cameras to have the peak sensitivities at specific wavelengths. The extreme example of it is LMS colour space which simulates the human cone responses. There are many possible valid spectral responses (infinite amount of them) all of which provide the accurate colour reproduction with varying perceptual uniformity (and the primary colours are not restricted to R, G and B either) - another example is XYZ space.

3) It is not possible for all cameras to have same peaks, sensors are compromised with regards to even more basic things.

The peak sensitivities vary from camera to camera. Here is an album of some images I have.

IR filter present in all consumer digital cameras shifts the peak sensitivity of "red" channel and also masks secondary extremums in the IR range). Here is a spectral sensitivity graph from Nikon D80 with IR filter removed:enter image description here

  • \$\begingroup\$ Yep - that bump in the NIR is typical of many blue filters, as is a bump in the blue-green for Red filters. \$\endgroup\$ Jun 23, 2016 at 12:00

My experience with photo imaging allows me to conclude that the filters used must mimic the tried and true “Three-Color” filters traditionally used on the film camera. These are the Wratten #25 Red – Wratten #58 Green – Wratten #47B Blue. The Wratten numbers are come from the catalog of the master filter maker Frederick Wratten of the London firm of Wratten & Wainwright purchased by Kodak many years ago. The photo industry continues to use the Wratten specifications and nomenclature. Wratten 47B Blue peaks at 425 Nanometers Wratten 58 Green peaks at 525 Nanometers Wratten 25 Red peaks at 700 Nanometers

You can find the spectrophotometric curves for these filters on the web.


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