Digital cure for mercury light?
Taking pictures in available light is very frustrating at times. Tungsten lighting has become rare, fluorescent energy saving lamps are the rule and most LED lamps also use fluorescent dyes. The result is a green/cyan cast mostly due to the spectral peaks of mercury in these dyes at the wavelengths of 546 nm and 436 nm I think. The hue slider should be able to cure that but frequently it doesn't, at least not sufficiently. Yellow tones like blond hair often retain a greenish tint. If you shift the hue far enough towards magenta to cure that, the skintones turn too pink. To me it appears that the green/cyan cast is not a shift of all hues but the excess of two specific colors or light wavelengths. That’s why shifting all hues with the tone slider (turning the color wheel) does not solve the problem, the peaks are moved but not weakened or cut out. Is that correct or a misconception? Of course the remaining green/cyan cast can be somewhat fixed by selective color adjustments or by creating specific color profiles but now things are starting to get too complicated for a common problem.
What we need I think is a "fluorescent fix slider", a third color adjustment slider that specifically deals with the mercury light peaks, similar to an adjustable notch filter in audio. Is that a feasible concept (at least theoretically) or just wishful thinking? We can specify skintones in RGB values so specifying two single colors should be possible too. The problem is not new. I remember that some Fuji negative films used to have an additional layer that dealt with the green/cyan cast of fluorescent lighting.
What we need I think is a "fluorescent fix slider", a third color adjustment slider that specifically deals with the mercury light peaks, similar to an adjustable notch filter in audio. Is that a feasible concept (at least theoretically) or just wishful thinking? We can specify skintones in RGB values so specifying two single colors should be possible too. The problem is not new. I remember that some Fuji negative films used to have an additional layer that dealt with the green/cyan cast of fluorescent lighting.
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Alternatively, you can tweak less-globally via the curve tool, or even the advanced color editor (which will also allow you to exclude/retain skin tones). This is your best option.
There were, in fact, fluorescent balanced films (but at the moment they escape me). There are also filters to go in front of the lens. These all presented their own bias and had their own flaws.0
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