hello,

I was recently asked in an interview
"Which are the two main colours of concern along the Kelvin scale in video"
Green and Blue
or
Red and Green
or
Black and white.

I never came to a situation like the above before, and i was wondering if anybody can give me an answer and why please.

I pressume this has to do with possible clipping or colour wavelengths that video cannot record properly or IRE relevant issues when editing in FCP ?

Any answers will be appreciated
Thanks

---
Vassilis Triantafyllidis
www.LemnosExplorer.com

In practical photography the illumination varies from about 2000K candlelight to about 15000K north skylight. A decent estimate of the color temperature can be had by comparing the Blue and Red exposures, representing the short and long wavelengths, respectively, while the Green exposure is held constant.

This graphic shows the spectral power distributions for seven different blackbody illuminations and also the spectral sensitivities for a typical TV camera.

Candlelight is extremely Blue poor/Red rich. Skylight is definitely Blue rich/Red poor. The cameraperson is expected to obtain good pictures in all cases. There are optical filters which correct the spectral distribution but at high cost to exposure. There are also the separate gain controls.

In reality, with candle illumination white things look quite white while the candle flame itself looks yellowish. In typical color photography, with candle illumination white things look yellowish and the candle flame itself looks white. That's a good conundrum.

Dennis Couzin
Berlin, Germany