Filters, Colour and White Balance

Colour / Whitebalance

Since colour was first used in photography, colour balance has always been a problem. Our eyes automatically adjust, so we see the correct colour whether in daylight or tungsten (artificial) light. How clever nature is! But film is not. Photographs taken in late evening, as the sun settles low, look much redder than from the eye when using daylight film. The same film used in artificial light ends up with an unnatural orange cast

In artificial light (3,200?K or below) it is necessarily to correct daylight film with a blue filter on the lens, or electronic flash, or blue flashbulbs.

In white daylight (5,900?K to 30,000?K) artificial light film needs to be corrected by using a pinkish filter(eg Wratten 84, Cokin etc).
 
 
 
 

Colour temperature

The same problem applies with video. if the window is small, a Wratten 84 filter gel could be fixed to the outside of the windows and the camera set for artificial light. Alternatively, use blue

‘daylight’ bulbs for the artificial light and set the camera for daylight.

Professionals use Kelvin meters to test the colour temperature and then use filters to even out the light sources. There is a large choice of filter for use with film. Electronic setting using video is simpler, but flexibility depends on the degree of sophistication of your camera.

White balance:

Average artificial light = 3,400?K

Average daylight= 5,900?K.
 
 
 
 

Day shots at night

Video is corrected electronically by setting the white balance. With some video cameras the colour setting is automatic. In bright daylight a very pale orange or reddish filter would probably improve the daylight colouring by reducing the slightly bluish light, but only when the sun is at its brightest.

Alternatively, for those with white balance sensors separate from the lens, placing a pale blue gel over the sensor might warm up the shadows. NB NOT over the lens, which would have the opposite effect of making the picture more, not less, blue.

More sophisticated cameras set white balance through the lens using a translucent white lens cap.

Professional cameras (and some domestic models) have a facility for setting white balance by pointing at a white card before starting to shoot. This can correct the white balance over the whole range of, say, 3,200?K to 30,000?K.

But indoors doesn’t necessarily mean artificial light, especially next to a large window on a bright day. In that case the video camera would need to be set for daylight

The biggest problem is when light is mixed, for example in an artificially lit room with natural light coming in from a window, if you were using artificial light film, you would need blue gels on. all the lights and to use a Wratten 84 (light orange) filter on the lens.

by Jon Woolmer