Color temp

[Ckulakov]

Dear Filmmakers,

 

I am a student and have a couple of questions. This has been bugging me for a while. If I purchase a full blue CTB rosco cinegel will it make things look blue in color or will it be close to matching daylight coming thru a window? To me it seems that when you use a CTB gel it gives actual blue color but daylight from a window looks white how do I get a white color temp using a CTB gel? And finally what is a basic definition of negative fill? Please help me by giving me honest helpfull replys.

 

Thank You in advance.

 

Constantine

[David Mullen ASC]

"Photographic" daylight is 5500K -- true daylight is a mix of colors in that range that varies throughout the day. A Full CTB gel converts 3200K to 5500K (tungsten to daylight). Otherwise in a daylight situation, a tungsten light looks ORANGE in comparison, so you use the Full CTB gel on the tungsten lamps to match them to the color of the daylight.

 

"White" is made up of all the colors. You have to decide what "white" is -- in your case, daylight is your white so an orange-ish tungsten light needs blue gel to make it as "white" (i.e. as blue) as daylight is.

 

Then, if you are shooting on tungsten-balanced film stock, now that all of your lighting has been matched to daylight, you need to use an orange filter on the camera (the #85B) to make daylight into the same color as tungsten (convert 5500K to 3200K.)

[Gordon Highland]

Negative fill is darkening an area of the frame, usually with a large solid black flag. If I'm shooting a talking head that is too flatly lit, and I want to give it a little character and model the face more, i'll bring in a flag on the opposite side of the key light (out of frame) and it will reduce the amount of ambient light hitting it from that side as well as bouncing less from the key light.

 

Once you understand color temperatures and matching them as per David's explanation, you can also use "wrong" mixtures of gels and/or source type and/or daylight/tungsten stock as an effect, such as having the background in blue hues and the characters in warm orange tones. The nighttime apartment scenes in "Eyes Wide Shut" demonstrate this very clearly. Or you can use it to tint a whole scene a certain color (I shoot video most of the time and will sometimes white balance using a slightly blue card to trick the camera into warming up the scene or orange for the opposite).