White balance is a setting in digital photography and image processing that adjusts the colors in a photograph or video to make the lighting appear more natural. The goal is to ensure that white objects are rendered as true white and other colors are accurately represented without any color casts.
In digital cameras, the white balance setting compensates for the differences in color temperature of various light sources, such as daylight, incandescent bulbs, fluorescent lights, and different types of flash. Each of these light sources has its own color temperature, which can affect how the camera captures and reproduces colors. For instance, photos taken under tungsten light (like in an indoor room) might have a yellowish tint, while photos taken under fluorescent light might have a greenish hue.
White balance can be set automatically by the camera (Auto White Balance or AWB) or manually by the user according to the type of lighting present. Common white balance settings include:
1. Auto White Balance (AWB): The camera selects the most appropriate white balance based on the scene's lighting conditions.
2. Daylight/Sunny: For use in direct sunlight or under clear blue skies.
3. Shade: For use in shaded areas where the light is cooler and bluer than in direct sunlight.
4. Cloudy: For use on overcast days, which have a slightly warmer, more blue-toned light.
5. Tungsten/Incandescent: For use with traditional indoor light bulbs that emit a warm, orange-yellow light.
6. Fluorescent: For use under fluorescent lights, which have a cooler, green-blue color temperature.
7. Flash: For use with the camera's flash to ensure colors are correct when the primary light source is the camera's flash.
8. Custom: Allows you to set a specific white balance based on a white or neutral-colored object within the scene.
9. Kelvin (K): Provides manual control over color temperature, allowing photographers to fine-tune the white balance according to the exact lighting conditions in degrees Kelvin.
By setting the correct white balance, you can ensure that your images maintain the desired color tone, making them look more realistic and consistent across various lighting conditions. Post-processing software also allows you to adjust the white balance after the image has been captured, which can be particularly useful when you're working with raw image files.