Balancing for tungsten lights

[Lenny Eiger]

I've been trying to find the best way to properly use daylight film to shoot under tungsten lighting. I've shot using the 80B and A filters(didn't see much of a difference). I've also tried to correct in Photoshop. It works but I'm having some difficulty getting really white whites. I'm shooting Fuji Velvia 50 @8x10. Any suggestions?

Thanks!

Al

Uhhh, don't do this. If you are concerned about those whites, shoot with the right color lights... (Its the same response to the "Doc, every time I slam my head against this steel door, it hurts" question.)

I have a set of TOTA Lights I bought a few years ago. They are now used as lights in my garage for doing other things.... Even tho' you might even get some on evilbay, Tungsten balanced film is gone...

There are many fluorescents and LED bulbs that are in the 5000K range. Personally, I'm not a fan of strobes, even tho' I used them plenty. There are many options from dirt cheap to very expensive. I just bought some fluorescent bulbs for the studio lighting for $5 each. A cheap ballast or two and you can be set up. Not the best solution by any means, but a lot closer than tungsten lighting would be.

Lenny

[Leigh]

There are many fluorescents and LED bulbs that are in the 5000K range.

Be very careful about claims regarding color temperature.

CT measures the ratio of red to blue components of light. It knows absolutely nothing about green.
One 5000°K light could look as green as a traffic light, and another of the same CT could look fully magenta with no hint of green.
This is why modern color temperature meters give a green/magenta correction in addition to the measured CT.

CT was developed before fluorescent lights existed, when all light sources conformed to the standard thermoluminescent curve like sunlight.
Since the shape of that curve is very well-defined, you could infer the intensity of green from the ratio of red to blue.
Secondary or ionizing emitters like fluorescent lights do not conform to the thermoluminescent curve.

- Leigh

[Bob Salomon - HP Marketing]

I mean common household tungsten lights.

You are not going to be able to correctly color balance them. They are about 2600K (40W household lamp) when new and used at the rated line voltage. They will drop about 100K with every hour of burning time and they will change color temperature and output with every drop in line voltage. In addition they will drop output as they age as the by product of the filament burning is deposited on the inside globe of the bulb (which is why the bulb darkens with age).

Go to the hardware or lighting store and replace the tungsten bulbs with compact CCFL bulbs with a color temp as close to 5000 K as you can find. That should make life a lot easier and keep the heat down as well as the electric bill. Maybe even eliminate the need for filtration as well.

To see what the ration of R to B to G is look for lamps with a high CRI index (color rendition index) lamps with a CRI of 90 or greater are needed for good photogaphy. A CRI of 95 to 98+ is best and will have the most accurate mix of colors. You might not find high CRI lamps at the hardware store. CRI is also used with 3200K flourescent tubes.

[Leigh]

You are not going to be able to correctly color balance them. They are about 2600K (40W household lamp) when new and used at the rated line voltage. They will drop about 100K with every hour of burning time and they will change color temperature and output with every drop in line voltage.

You can accurately balance any thermoluminescent (tungsten, halogen, etc) light source.

Nobody would even consider using a 40-watt bulb for photographic applications. Large halogens are much more appropriate.

The 100°K per hour drop makes no sense. If that were the case the lamp would dim completely after only one day of operation.

Yes, any thermal emitter will change intensity and color temperature with fluctuations in line voltage.

As I've mentioned elsewhere, color temperature is only part of the picture. It says nothing about green, which is a problem with fluorescent lights.
The CRI is a much more accurate measure of how a bulb will perform in a photographic situation, but it's still not the whole story.
You need a good color temperature meter with a green/magenta channel to properly evaluate any light for photographic use.

- Leigh

[Bruce Watson]

I mean common household tungsten lights.

Then, as Lenny suggests, you are just beating your head against the wall. Common household tungsten lights vary all over the place. Unless you're willing to spend a fortune on instrumentation, you'll never know what you've got. And that makes it damn near impossible to correct for it. Better to spend that money on some decent lights designed for the duty, and some film that isn't in the running for the most picky film ever created.

[brucetaylor]

What Bob Salomon said. I have some motion picture backround, and balancing between tungsten, daylight and non-corrected flourescents are common. Common houshold lights are often used in frame as an accent or as a motivation for a larger corrected source outside the frame, but generally not as a primary light source. The color temp is all over the place, and they DO reduce color temp as they burn. In the early days of color before halogen bulbs they had a guy on every tungsten fixture (that's what I heard, I'm not old enough to have been there!) with a pile of color correction gels and the DP walking around with a color meter. I would suggest you use lighting that is designed for the use you intend. Rent them if you need to, any good sized city will have a rental house. Or if you buy, get fixtures that are made for photography/cinematography and have consistent color temp and sufficient CRI (like Bob says, 90 or better). Standard color correction techniques work fine (80 filter over the lens for tungsten or gel tunsten with full CTB). Photographic LEDs and flourescents work fine too, they cost more because the temp and CRI are within spec. CRI is important with these sources, you can't edit spectrums of light in post if they aren't in the light to begin with.