The most extreme example in common use is probably low-pressure sodium lamps (those intense yellow-orange streetlights), which emit almost exclusively at two very close wavelengths, 589.0 and 589.6 nm.
Yep—if you take photographs under these lights (e.g. night street scenes), you essentially get tinted monochrome photographs. Under an almost-single-wavelength source of light there are no colors, only illumination intensities.
Yep—if you take photographs under these lights (e.g. night street scenes), you essentially get tinted monochrome photographs. Under an almost-single-wavelength source of light there are no colors, only illumination intensities.