Lighting question

GREAPER

I have an odd question maybe someone can answer.

The electrical contractor I work for has been asked to handle a lighting situation for the Maumee police department.

We recently helped construct a new police station for the city of maumee, Ohio. There is a room in the police station where they take the mugshots of people who have been arrested. They are currently getting a yellow cast to the photos. They have asked us to color correct the lighting in this room. Aparently they are not photographers and do not know how to, or want to correct the color cast photographically, they want us to color correct the lighting.

Does anyone know:

a) the kelvin temperature of "normal sunlight" lighting where there willnot be a color cast to daylight balanced film?

b) What type of "hotlight" lamp gives of this temperature of light?

Nikolai

Hey Greaps,

GREAPER wrote:

Does anyone know:

a) the kelvin temperature of "normal sunlight" lighting where there willnot be a color cast to daylight balanced film?

b) What type of "hotlight" lamp gives of this temperature of light?

I don't know the said scientific facts, but the ACR is my friend, so I opened first .cr2 file I could find and played with WB settings. Out of three natural sources it gave me the following:

• Daylight: T=5500K, tint=+10
• Cloudy: T=6500, tint=+10
• Shade: T=7500, tint=+10

I'd say that pretty much answers your question #1.:D

As to your second question: again, I did't have the answer on top of my head, but Google (or, actually, Froogle :-) is my friend, and if you froogle for "hot light 5500K", you'll get a pretty good idea on what's on the market.:):

HTH

PS
You're coming to Bryce and Zion, aren't ya?

GREAPER

yep. My wife and I are comming. I can't wait.

Just so you know, you were more help than you might think. I used the info you gave me to find daylight balance flouresent tubes that can replace the existing cool whites to solve the problem.

I am going to go meet with thier photgrapher to find out what film and camera they use and we will be able to solve their problem.

Nikolai

Kewl!

GREAPER wrote:

yep. My wife and I are comming. I can't wait.

Just so you know, you were more help than you might think. I used the info you gave me to find daylight balance flouresent tubes that can replace the existing cool whites to solve the problem.

I am going to go meet with thier photgrapher to find out what film and camera they use and we will be able to solve their problem.

Glad to be helpful, at least occasionally... :
Cheers!
PS
Check your PM:-)

Andyman

They're generally used outside because of their brightness etc, but you might want to check out metal halide lighting as it does not emit those yellow hues (generally these are the blue/green lights you see at night on streets or buildings. High pressure sodium or incandescent are generally the yellow lights you see on buildings).