I've seen many photos where the bloom has a color close to the color of its source.

From what I've read, the bloom is caused by an overflowing of the potential well into neighboring sensors. Since this happens after the color filtering, the bloom should be completely white every time, no?

It's a bit hard to find an example since people avoid taking pictures with bloom, but this looks like what I'm talking about:


Did I understand it wrong, or is it caused by other effects?

EDIT: found some better examples:

Bloom in strobe lights

Video of a blue strobe light


Because you have three channels of color information (red, green, blue), and not all of them saturate at exactly the same level, unless the object being (over-)exposed has exactly equal levels of each of the wavelengths that are passed through the mosaic filter in front of the sensor.

  • Would you know why they saturate at different levels? Do the potential wells have different capacities? Apr 10 '18 at 15:46
  • 1
    @BernardLupiac Each channel has different sensitivity at different wavelengths. The source is not monochromatic.
    – Stan
    Apr 10 '18 at 16:34

There are different ways for this effects. One is a electronical misinterpretation on the sensor (the long white solid beam horizontal or vertical on the sensor), I don't know how this exactly works, but somebody explained to me that the charge on a singe pixel is that high, that it affects other pixels in that row in the process of reading out the sensor. The other effect maybe is the possibility of diffraction on the aperture blades in combination with the different refraction angles of the different wavelengths of the light.

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