white balance
By so called chromatic adaptation the human eye respectively the brain manages to always capture a white object as truly white – no matter if in natural or artificial light. Otherwise a white object would appear with a blue color fog under a cloudy sky or with a red color fog in candle light.
Digital photo cameras however have no built-in chromatic adaptation system (yet) and hence work with the so called white balance method, also known as color balance, color correction gray balance or neutral balance. The camera’s image sensors capture the so called color temperature in the current lighting situation. Each source of light has a different color temperature, measured in Kelvin (K) – some for skateboard photographer relevant examples: street light ~3.000 K, photo lamp ~3.500 K, daylight ~5.500 K to ~7.000 K, bright sunny day ~9.000 K to ~12.000 K.
Different color temperatures are saved in your digital photo camera and with information of the built-in image sensor settings a photo without colour fog can be configured.
AUTOMATIC WHITE BALANCE
For an automatic white balance your photo camera looks for a white or at least neutral gray surface at the skate spot and adjusts all other colors accordingly. This automatic color balance of today’s digital cameras is very reliable and works particularly well with fast changing light situations (e.g. sunshine through a cloudy sky).
However the automatic color correction fails when the image sensor can’t pick up a white or neutral grey surface (e.g. in twilight) and takes the brightest colored surface instead. This often leads to a misinterpretation of the color temperature and the skateboard photographer has to fall back on a manual color balance to avoid color fog.
SEMI-AUTOMATIC WHITE BALANCE
In case the automatic color correction fails photo camera manufacturers have saved special white balance pre-settings on their devices. Thus the skate photographer can select typical color temperatures for different lighting situations (e.g. bright sunshine, cloudy sky or street lights). With some cameras you can even set the exact color temperature in Kelvin.
However for a semi-automatic color balance you have to assess the lighting situation accurately. Or you could color your photos red or blue with knowingly wrong settings.
MANUAL WHITE BALANCE
If even the pre-settings fail the ambitious skate photographer has to work with a manual color correction: Hold the camera on a white or at least neutral gray surface at the skate spot you are shooting. Usually a white sheet of paper does the job, however professionals work out their manual white balance with a 17,68% reflecting grey card. Then you shoot a reference photo and the camera’s image sensor will adjust the right color temperature.
SOFTWARE-CONTROLLED WHITE BALANCE
If you have taken your photos as so called raw image files you can add a subsequent white balance using special image processing software – you can even differentiate between automatic, semi-automatic and manual methods. For example for a manual color balance you simply choose the white or gray surfaces with point-and-click.