 Justin B. Renshaw |
colors of different lights What is the type of light that renders white light? Ex:Halogen=yellow-red flourescent=yellow-green etc... Thank you for any help
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Mark Feldstein |
If you're referring to color temperatures of various kind of lighting, then perhaps a booklet on filters will help you out in terms of how to correct one type of light back to daylight temperature which is about 5500 degrees on the Kelvin scale. The temperature of tungsten lighting, i.e., various kinds of incandescent lighting is cooler than daylight and varies according to exactly what kind of light it is. For example, photofloods are about 3600 to 3400 degrees Kelvin while household lightbulbs vary from around 1800 to 1600 degrees. Halogen lights also vary. When they're new, I'd have to guess that they're somewhere in the middle between photofloods and daylight. But as a bulb or more correctly, the filament, ages, then they start cooling off to a lower color temperature. As to flourescent lights, there are many different types of tubes including daylight tubes that produce warmer light than the yellow/green type. You'll also find that different kinds of sodium or mercury vapor lights, like the kind found in parking lots, industrial plants and gymnasiums, illuminate at different temperatures and cause color shifting. While knowing the type of light you're dealing with and trying to compensate for is very helpful, the only way to know exactly how to compensate is to use a color temperature meter (similar to a light meter) which is a bit pricey. And (go figure) to use the meter, it helps to have a complete set of color correction filters. VERY pricey, but sometimes necessary for critical work. To make this even more confusing, you can make corrections for daylight film (5500), or tungsten film, 3400K. Sorry, I can't help you if you're shooting digitally or using photoshop. Nonetheless, the best aid I've seen for correcting various color temps or adjusting color shift for one type of lighting to various types of film, particularly daylight or tungsten, (especially useful with transparency films) is in the Kodak Professional Photoguide. It's their publication number R-28. And, it includes a good discussion on use of filters AND a color temperature correction wheel. Some color corrections can be made during the printing process. And, you should know that tungsten light impacts black and white film as well as color. To clean up the whites with b&w try using a #12 yellow. Remember, a filter filters out it's primary color and let's the spectrum through. :>) [No charge here for the physics lesson] but I hope this helps. Meanwhile, take it light, Justin. ;>)
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Justin B. Renshaw |
Thanks for the insight on the Kelvin scale. What I was wanting to know is what kind of light bulb is use in studio lighting. You know, are they flourescent, halogen, tungsten( I know it's none of these )
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- Gregory LaGrange Contact Gregory LaGrange Gregory LaGrange's Gallery |
1.Flash tubes 2.Incandescent with glass with a blue tint Special flourescent with a tri-phosphor(could be called another kind of phosphor) coating inside These can be used to get closer to sunlight. The daylight balanced flourescents are closer to daylight than daylight incandescent. Brighter too for a given power amount. The color temp for regular house bulbs mentioned above sounded too low. Think it's in the high 2000 to low 3000 range.
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