Shedding New Light on Darkroom Illumination
Film also has a spectral response. This slide shows the spectral response of EASTMAN EXR™ Color Print Film. Other color print films have a similar response, as do color intermediate films used for making master positives and duplicate negatives. Note that there are sensitivity peaks in the blue, green, and red portions of the spectrum, with "valleys" of less sensitivity in-between. The lowest "valley" of sensitivity in the visible spectrum is between the green and red, at about 590 nanometers.
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