fluorescent lighting question

Mark McCann · August 4, 2010

Hey all im a first year student filmmaker in the u.k, and aspiring cinematographer.

I have a question about using fluorescent lighting in scenes. I know that tungsten lighting is about 3200k and is quite yellow/redish and outdoor light is for the most part 5600k and is quite blueish. fluorescent lighting confuses me, i know it gives off a greenish tint [am i correct so far in what im saying?] but what color temperture does it have?

would fluorescent lighting be balanced closer to indoor lighting or outdoor lighting, im interested in making a short film this year which has been in my head for a long time, and a few of the scenes would be made with fluorescent lighting to give the sort of feel seen in some parts of fight club, but i need to know the specifics of using it so i can grasp how to work the lighting.

If anyone can help me with telling me a little about balancing for fluorescent lighting, and what color temperture it is, it would be fantastic.

vive le cinématographie

Adrian Sierkowski · August 4, 2010

Depends on the bulbs. It ranges from 3200K through the 4000K (4800K is where I normally park a "typical floro) up through 6500K and sometimes higher. It's not that the light itself is necessarily green, but it appears green on camera because of it's discontinuous spectrum.. it has highpoints and low points, and a lot of the cheaper ones have a strong green spike in their signal- oft missed by human eyes, or better put, auto adjusted for. How a floro will look will depend on the tubes you use (look for their CRI, the lower the CRI the greener they are, anything over 90 is ok enough to be taken as it says, e.g. 5600K) and the camera you're using.

You can pick up cheap shop lights from home-depot ($9USD for 4' banks last I bought them) and a few tubes as well and test them all against each other and against the camera's balance as well. Were it me, I'd start with 3200K balance on the camera, and "warm white" floros, and then cool-whites.

Mark McCann · August 4, 2010

Depends on the bulbs. It ranges from 3200K through the 4000K (4800K is where I normally park a "typical floro) up through 6500K and sometimes higher. It's not that the light itself is necessarily green, but it appears green on camera because of it's discontinuous spectrum.. it has highpoints and low points, and a lot of the cheaper ones have a strong green spike in their signal- oft missed by human eyes, or better put, auto adjusted for. How a floro will look will depend on the tubes you use (look for their CRI, the lower the CRI the greener they are, anything over 90 is ok enough to be taken as it says, e.g. 5600K) and the camera you're using.

You can pick up cheap shop lights from home-depot ($9USD for 4' banks last I bought them) and a few tubes as well and test them all against each other and against the camera's balance as well. Were it me, I'd start with 3200K balance on the camera, and "warm white" floros, and then cool-whites.

ok great, thanks very much for the info. i think ill pick a range of tubes soon and test them. im still learning but to just to check, if i have a one with a low CRI, would i be able to offset the green with magneta filters? Again the info has been a great help.

Adrian Sierkowski · August 4, 2010

Yes, you can use minus green (magenta) on the tubes, or plus green on your lights (depends what you have more of, tubes or lights.. e.g. you'd not want to minus green a whole office building when you can just plusgreen the one or two other heads you're using). I'd recommend a color meter, or again, brute force testing, to help know how much -green or plus green you'll need for a given type of tubes/camera; though I'd say 1/2 either or the other is a "safe" bet that will require some finessing in post. Also depends what you're shooting. If i'm on stock, I'll often just say, ok, go with it, I can correct it later on in the TC (granted it's something i've encountered a few time so have an inkling what the colorist can marvelously do).

Mark McCann · August 4, 2010

Yes, you can use minus green (magenta) on the tubes, or plus green on your lights (depends what you have more of, tubes or lights.. e.g. you'd not want to minus green a whole office building when you can just plusgreen the one or two other heads you're using). I'd recommend a color meter, or again, brute force testing, to help know how much -green or plus green you'll need for a given type of tubes/camera; though I'd say 1/2 either or the other is a "safe" bet that will require some finessing in post. Also depends what you're shooting. If i'm on stock, I'll often just say, ok, go with it, I can correct it later on in the TC (granted it's something i've encountered a few time so have an inkling what the colorist can marvelously do).

im going to see about a color meter, something on the cheap side that can do the job without going overboard on features. I think i will be plus greening some of the lights i have, its low microbudget so ill only have a few redhead's,blondes, didos, and kinos-which i think i can just add some preferred tubes too. im not sure what you mean by "TC", what does that stand for? im shooting digitally so is that a term associated with shooting on film stock?

Adrian Sierkowski · August 5, 2010

TC is shorthand for Telecine in this case, and color meters run over $1000 new; see if you can trck down a used one, or rent if needed.

Mark McCann · August 5, 2010

TC is shorthand for Telecine in this case, and color meters run over $1000 new; see if you can trck down a used one, or rent if needed.

ah ok that makes sense now. Will see about tracking down a used color meter, been wanting one for a while. thanks for all the info.

John Sprung · August 5, 2010

fluorescent lighting confuses me, i know it gives off a greenish tint [am i correct so far in what im saying?] but what color temperture does it have?

In the absolute sense, it doesn't have a color temperature. Only things that match the colors produced by hot objects -- like the sun, or the tungsten filament in a light bulb -- have color temperatures. Things that sorta come close are assigned "Correlated Color Temperature" and "Color Rendering Index", which are kinda bogus. CRI, in particular, is defined for human vision, not intended for film or video/digital cameras. Theoretically, you'd need to define a CRI for each film stock and each electronic camera. But in the largely bogus kinda close enough world of CRI, everybody just uses the human vision version of CRI.

If you really want to know what's going on with this, find out about CIE 1931 (x,y) space.

-- J.S.