PDA

View Full Version : Why is Fluorescent tricky?



Geoff Chandler
02-05-2008, 09:19 AM
Often in camera tests half decent cameras produce strange coloured images in fluorescent lighting. Sometimes Auto White Balance just doesn't cope, sometimes it does, if you are lucky.
So - what's that all about?
Well - in normal everyday situations Auto WB will work quite well - and so will the varous others - like Dayling/Sunshine WB or Cloudy WB ~ these are all just different colour temperatures set in the camera to make it easier for us.
The more experienced photographers will sometimes manualy select their own colour temperature (eg 5300K for a daylight photo - or 6000K for a cloudy - or 3300K for indoor lighting of the filament type (tungsten/Incandescent)
The problems start when we encounter Fluorescent tubes and the like.
ordinary lighting , and tungsten lighting, range generally from the redder end of the spectrum to the bluer end. But Fluorescent tubes have a bit of green thrown in. So no matter how you fine tune your WB unless you have a fluorescent setting - or your camera has a fine tune Green ~ Magenta it will never look quite right.
Also - once into your Fluorescent setting - it is wise to then do a few trial shots as you will still need to tweek the colour temperature up or down.
Below is an example of 3 shots taken, at night in an office with fluorescent lighting (to ensure no other light affects the experiment).
TOP is a photo taken using a Manual White balance at 3700K - actually the correct colour temperature in this location. But NOT fluorescent.
MIDDLE is using the standard Fluorescent setting, actually 4200K in my case, but with the Green/Magenta difference.
BOTTOM is Fluorescent setting (in my case +1) which is 3700K
~ Notice, particularly, the difference between the two pics at 3700K !!
THAT is what the fluorescent setting does..
(Personally I would like a fine tune Green - Magenta - but you can't always have everything!!)

I hope this helps someone somewhere.
:)