Color Temperature and White Balance
Explore Landscapes #45
Unusual colors in your photos? White balance helps to achieve the most accurate colors in an image by reducing (or eliminating) a color cast.
Image Source: Adobe Express
Every light source, such as the sun, the moon, a candle, or artificial light (such as a tungsten bulb), casts a specific color of light. That color is the light source's color temperature, i.e., the light's relative warmth or coolness, measured on a scale with Kelvin (K) units.
The lowest numbers on the color temperature scale are the warmest. For example, a candle flame appears orange/yellow with a color temperature of about 1,800 K. The higher numbers are cooler. For example, outdoor shaded light appears blue and has a color temperature of about 7,000 K.
That color cast may affect the colors in a scene, making objects that should be white appear cooler (i.e., more blue) or warmer (i.e., more orange/red). Our eyes may not perceive this color cast, as the human eye adjusts very well to different types and brightnesses of light. However, our camera will record the color cast by the light source, whether the yellow light of sunrise (2,500 K) or the midday sun (5,500 K).
White Balance Settings | Image Source: Adobe Express
If, when reviewing your images, you detect an unusual color, then your images need to have the color temperature adjusted so that the colors in your scene are rendered accurately (or not - I'll come back to this in a minute).
White balance refers to achieving the most accurate colors in an image by reducing (or eliminating) a color cast either in the camera or during post-processing.
To adjust the color temperature in your image, white balance adds the opposite color to the image to try and bring the color temperature back to neutral, i.e., whites appear white in your image. So, in fact, color temperature and white balance are opposites.
Sunrise image with White Balance from 2,000K to 10,000K | © 2024 Jon Norris
Most cameras have various white balance presets, including Cloudy, Tungsten, Fluorescent, Daylight, Flash, Shade, and Auto, that you can set in-camera for different lighting situations. However, there may not be a white balance setting that is exactly right for the lighting situation that you're photographing.
I suggest you don’t shoot in auto white balance (AWB) but fix your white balance on one of the other settings. If you set auto white balance and shoot, for example, a series of images to use in an HDR image, panorama, or focus stack, each image will have a different color temperature, which makes blending exposures very difficult. I keep my white balance set to shade and adjust as required in post-processing to avoid this.
If you shoot in RAW, you can adjust the white balance in post-processing, as it’s not ‘baked-in’ as it would be if you shot the scene as a JPEG (read this if you'd like a refresher on RAW vs. JPEG to help you decide which format you should shoot in). I'll cover how to adjust the white balance in post-processing in a future post.
Calibrated Color Card | Image Source: Adobe Express
If accurate color is important, consider photographing a calibrated color card in the same ambient light as your subject. Then you can use these known colors to adjust your color temperature / white balance accordingly.
Depending on your artistic intent for photographing a specific scene, you may not want the colors to be 'rendered accurately'. For example, you may want to 'warm up' a sunrise to better convey the warmth of the early morning light. Alternatively, you may want to 'cool down' the sky on a rainy day to make the scene appear colder and dreary.
