WHITE BALANCE

WHAT IS WHITE BALANCE? White balance (WB) is the process of removing unrealistic colour casts, so that objects which appear white in person are rendered white in your photo. Proper camera white balance has to take into account the "colour temperature" of a light source, which refers to the relative warmth or coolness of white light. Our eyes are very good at judging what is white under different light sources, but digital cameras often have great difficulty with auto white balance (AWB) — and can create unsightly blue, orange, or even green colour casts. Different kinds of lighting look the same to the human visual system (although once you, as a photographer, know that there is a difference, you'll look for and notice it everywhere!).

WHAT IS COLOUR TEMPERATURE? So what is colour temperature? In short, each light source has its own individual colour, or ‘colour temperature’, which varies from red to blue. Candles, sunsets and tungsten bulbs give off light that’s close to red (hence the ‘warm’ look they give to pictures), whereas clear blue skies give off a ‘cool’ blue light. It’s fairly obvious stuff once you read it. Colour temperature is typically recorded in kelvin, the unit of absolute temperature. Cool colours like blue and white generally have colour temperatures over 7000K, while warmer colours like red and orange lie around the 2000K mark.

WHAT IS THE KELVIN SCALE? The Kelvin scale is used in the measure of colour temperature. In photography the Kelvin and colour temperature is used in a variety of ways. For example, colour temperature lights can be set as ‘daylight balanced’. A ‘daylight balanced’ light will radiate light that matches a colour temperature determined as daylight

WHAT HAPPENS WHEN WHITE BALANCE IS WRONG? A picture taken with a normal white balance under artificial lighting conditions transmits the low heat to the camera’s sensor. This light touches the red bits of the spectrum, which results into dull yellow or orange shades in the picture.

EXAMPLES OF WHITE BALANCE:

HOW DO YOU SET WHITE BALANCE ON CAMERAS? Find the white balance control on your camera. See your manual for details, but here are a couple of hints: Digital SLRs will usually have a button on the top or back of the camera that says "WB". You hold the button down while spinning one of the control dials, to adjust it. (The cheaper Nikon digital SLRs omit this).

PANASONIC AVCAM 90 & 151