I was looking at a beautiful rainbow tonight and it occured to me. What would you see if you took a picure of a rainbow with black and white film… what about with a regular digital camera then changed it to black and white. What if you were totally color blind… what could you see? Obviously there is nothing physical to see other then light and color.
However, i know that if you take a b&w film pic of clouds in the sky, you dont see much but if you use a red filter the clouds look white and the sky black… so its sensitive to color somehow.
If all the colors of the rainbow were the same luminosity, and the camera was equally sensitive to all colors, you would see a grey bow, with no bands in it.
Just because you can’t tell different colors of light apart doesn’t mean that you can’t see the light. In black and white, a rainbow would appear white.
And the color sensitivity in your cloud example comes from the red filter, not the film.
Well, sort of. B/W film is color sensitive, but it doesn’t separate them. Different types of B/W film have varying spectral sensitivities. The first B/W films were only sensitive to blue, and later, green light (orthochromatic). Panchromatic film emerged in the early 1900s, which added red sensitivity.
The red filter works by only allowing red light through. The light from the sky has a negligible amount of red light, so very little light from the sky makes it through to expose the film. A red filter wouldn’t work with ortho film.
I thought this would be a thread about yet another Elton John self-cover of Candle In The Wind - perhaps to mark the passing of Pavarotti or something…
Anyway… it depends on the spectrum of sensitivity of your film or digital sensors - some ordinary cameras can already pick up more than the human eye can detect, but it’s also possible that, for example, if your film was sensitive only to a few narrow bands of visible light, that your rainbow would come out looking stripey.
