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White Balance and Color Temperature Explained

by Dan Bailey on July 9, 2010 · 4 comments

White balance is the adjustment that makes white look white

Let’s talk color temperature. We know that photography, just like human vision, is all about recording the light that’s being reflected back from our subject. Essentially, in order for photography to work, we need a subject and a light source. The subject part is easy, because whatever you put in front of your camera will have a consistent quality to it when you record your image on to the digital sensor. Your beautiful model will still be beautiful, the Grand Canyon will still be an enormous ditch in the desert, and that mountain will still be covered in snow.

However, the light is not so consistent. Depending on what time of day you take your photo, or whether you shoot inside or outside, or even if you shoot in the shade or in the direct sunlight, your photo will look remarkably different because it will have a unique color cast. As the sun travels across the sky, it changes in color throughout the day due to scattering of the light in the atmosphere. That’s why sunset light is red, mid day light is white and shadows have a pronounced blue cast. This is nothing new, and we take advantage of this every time we head out to take photos at Magic Hour.

Different types of indoor light have different color cast as well, but for a different reason. The color of an artificial light source is determined by the amount of thermal radiation that is re-emitted from a theoretical physical object that absorbs all electromagnetic radiation. This radiation is defined as color temperature and measured in degrees Kelvin.

This you know already know, and it’s why subjects shot under incandescent light have an orange cast and photos shot under fluorescent look green.

We don’t see these color casts with our eyes, because in the course of human evolution, it seemed to be beneficial for our ancestors to recognize objects under different lighting conditions throughout the day. Our brains learned to compensate for color casts. A piece of paper looks white to our eyes whether we look at it outside or under a desk lamp.

Camera sensors don’t compensate for color cast, which is why you occasionally need to set and/or adjust the White Balance in your images. White balance is the adjustment that makes white objects appear white in the photo, regardless of the lighting conditions. With film, we used colored filters to compensate for different color temperatures. Today, most digital cameras have an auto setting, which works pretty well, but experiment with yours, as you may find that setting the individual custom white balance may work better for you (sunny, cloudy, electronic flash etc…)

When shooting RAW and adjusting White Balance inside your RAW processing software, you may find that you need to tweak the white balance a bit. Usually, using Auto on Camera and As Shot in the software will get you pretty close, but if you need to make an adjustment, the easiest way is to use the White Balance Tool and click it on an area of the photo that is a neutral color, i.e. white, gray or anything that has no warm or cool tones. However, don’t try and adjust too much for sunset and magic hour shots, you generally WANT the to preserve the warm color cast that’s present under these lighting conditions.

Adjusting White Balance in Adobe Camera RAW

This should make the correction and give you an accurate color balance. If you need to fine tune the adjustments, make small movements with the blue/yellow or the green/magenta sliders. It should be apparent which way you need to go. Remember, if you mess up or go too far, you can always revert to your original setting or to the As Shot setting.

Don’t be intimidated by White Balance adjustments and settings, learn to use them with confidence. If you shoot RAW, I find it’s best to just use Auto and adjust in the software as needed. If you shoot JPEGs, you can’t go back and adjust White Balance later, which is one more reason to shoot RAW. However, it you just shoot JPEGs, you can try and correct with levels, curves or with the Color Balance tool.

For more information, here’s a good tutorial on White Balance.

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Dan Bailey is a professional adventure, outdoor and travel photographer based in Anchorage, Alaska. You can follow his own blog at danbaileyphoto.com/blog and see his daily Facebook updates at facebook.com/danbaileyphoto

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