Spectral color

Photography Cheat Sheet: Color Temperature and the Kelvin Scale

White balance, or WB, is necessary on cameras because light not only varies in brightness, but also in color. Each light source has its own “color temperature”, which varies from red to blue as you move through the visible spectrum. Human vision is very good at compensating for this, so a white sheet of paper will look white whether seen in daylight or candlelight. It’s the job of the camera’s white balance system to do the same thing and compensate for color differences in lighting, so that the colors in a scene look exactly the way we expect them to. were expecting.

Digital cameras have a wide range of options for controlling white balance based on the color temperature of light in the scene, including Auto White Balance (AWB), which will intelligently take care of all this for you. However, as with all automatic settings in your camera, auto white balance is not foolproof and may undercompensate for extreme conditions as it can only work in a restricted temperature range.

Click on the upper right corner to enlarge the image (Image credit: future)

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The Kelvin scale

Color temperature is measured on the Kelvin (K) scale and a camera’s automatic AWB system can usually only adjust between 3500K and 8000K. It will struggle to get an image that doesn’t look orange when shooting in your room before dark, for example, because the color temperature of household lighting will be lower. It can also struggle just before dawn, when the light is blue and has a higher color temperature than the auto setting can handle.

Your DSLR or mirrorless camera therefore has a number of manual white balance options that allow you to take full control. White balance presets are the easiest to use. These are settings designed specifically for different light sources, such as flash, incandescent light (domestic light bulbs), sunny days, cloudy days, or deep shade. They are useful for achieving consistent colors in a sequence of images or for tricking the camera into giving you slightly warmer or cooler results.

For more control over the color temperature settings, you have to use another manual option. Although not present on all models, the K setting allows you to set a specific color temperature. This is ideal for precise control as you can dial in any setting from, say, 2500 to 10,000K.

The custom white balance setting is more used and widely available on digital cameras. This is set by taking a measurement from a test target, such as a sheet of white paper. Just make sure it fills the frame and is in the same lighting you will be using for your photos.

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