Understanding & Correcting White Balance

What is White Balance?

Any time you take a photo of a solid white object, the color of that object will vary depending on color temperature of the source of light that is hitting it. This can range from very blue light to very yellow/gold light. Adjusting an image’s white balance refers to making corrections to the image (or adjusting settings on the camera prior to shooting) to, essentially, make the white point white. Without proper white balance, it’s impossible to get proper color in your photos.

White Point on Your Digital Camera

Most mid-range and up consumer digital cameras these days offer a variety of white point settings for different lighting conditions, natural, incandescent, fluorescent, etc. Some allow you to manually set the white point by first photographing a white object and then telling the camera to reference that as your white point.

While these methods often work well, they are not infallible and chances are, you’ll need to adjust the white point yourself in post-processing on more than one occasion, particularly if you do a lot of low-light phography.

Adjusting The White Point in Photoshop

There are a few methods for adjusting and correcting white balance in Photoshop. Some will work better than others, depending on the situation and the image at hand. The method illustrated below works most of the time.

Open your image in Photoshop and then bring up either the levels adjustment dialog (Ctrl+L) or the curves adjustment dialog (Ctrl+M). Personally, I generally work with curves as opposed to levels, but for many situations this is just a matter of personal preference.

Notice the three eyedroppers (this is an example of the curves dialog, but the levels dialog also has droppers which function the same way).

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 1

As you can see, the droppers are labeled in the diagram as “black,” “grey,” and “white,” which is also illustrated by the color of liquid the dropper contains. These droppers essentially function the same way that the standard eyedropper tool does, except that they pick up the tonal value of the image rather than the color.

So now click on the white dropper and then click on the brightest point on your image that should be white. This will adjust the image, making this setting your white point to reference that area as white.

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 2

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 3

This has made a dramatic difference, but, generally speaking, when we alter our white point, it throws off the black point, so we need to do the same technique, only this time let’s use the black eye dropper and select the darkest spot on the photo.

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 4

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 5

As you can see, this is a dramatic improvement from the first image:

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 6

To the final result:

Adobe Photoshop Tutorial - Understanding and Correcting White Balance - Fig. 7
If you find that your colors are still off, you can use the “grey” dropper to select a middle grey value, but I’ve found that usually this isn’t necessary. You can also fine-tune your results by going to Image - Adjust - Hue/Saturation, if you’re not totally satisfied with the above.

Added Wednesday, September 27th, 2006 at 9:51 pm under Photo Effects.