Making Image Color Balance Adjustments in Photoshop
Adapted from Photoshop CS2 Workflow: The Digital Photographer's Guide (Sybex)
Dateline: June 8, 2005
After you’ve optimized the overall tonality of your image (discussed in Evaluating Images and Adjusting Photographic Tonal Values), the next step is typically
color adjustments. At the most basic level, these include adjusting the color balance to
remove any undesired color cast or to introduce one that is desired, and adjusting the
saturation of colors within the image to taste.
Note: Photoshop Elements does not include a Color Balance adjustment. However, it does include other color adjustment options. You can use the Color Variations command (Enhance > Adjust Color > Color Variations) to adjust color balance by clicking the thumbnail at the bottom of the dialog box that represents the best color, selecting each best option in turn until you produce the best final result.
Instead, I feel the focus of a color balance adjustment should be to eliminate any color influence you don’t like and to add a color influence you do like. The result needs to be close to reality to be accepted by those who will view your images, but you do have a fair amount of latitude. Focus on producing the best aesthetic results, and you’ll be well on your way to accurate results as well.
The simplest way to make basic color balance adjustments is with the Color Balance dialog box. This dialog box includes three sliders as the primary controls (shown below). These represent the color axes for each of the three channels that make up your image. As an additional benefit, the sliders are labeled to remind you of the relationships between colors. Colors at opposite ends of a given slider are opposites of each other, and moving the slider in one direction or the other will cause the overall image to be shifted toward that color value.
The Color Balance dialog box provides sliders for each of the
three axes represented by the color channels that comprise an
image, and allows you to adjust the balance for color along each axis.
It is important to keep in mind that when you make a color balance adjustment to your image, you are adjusting all pixel values within the image. The key to understand is that just because you are moving a slider between cyan and red doesn’t mean you will affect only those pixels within the image that are cyan or red. Rather, all pixels within the image will be shifted toward the color value you choose with the slider.
As with other adjustments, the first step is to create a Color Balance adjustment layer; doing so opens the Color Balance dialog box. I strongly recommend starting with the axis that needs the most significant adjustment. For example, if you have an image with a magenta cast, such as the one below, start with the Magenta/Green slider.
If you have an image with a magenta cast, the Magenta/Green
slider in the Color Balance dialog box should be the first you adjust.
When adjusting a given slider, especially if you are not yet comfortable with visualizing the particular adjustment required, I recommend moving the slider through the extremes of its range. Besides helping you get a better sense of where an appropriate color balance exists for a particular slider, this process will also help you develop your skills for understanding how a particular adjustment will affect various color and tonal values within your images. As you move the slider back and forth, starting with the extremes, gradually zero in on the range that seems to provide the most appropriate balance for that channel.
With the slider positioned as accurately as possible with the mouse, you can then take advantage of keyboard shortcuts to fine-tune the adjustment. After you have moved a slider, the text box that holds the final value for that slider will be active. You can then use the up and down arrow keys on your keyboard to adjust the value one unit at a time.
In the case of the sample image with a magenta color cast, your first step would be to shift the color balance toward green by using the Magenta/Green slider (see below). This will effectively neutralize the unwanted magenta color cast, producing an image that is relatively neutral with accurate color.
A magenta color cast can be corrected by moving the Magenta/Green
slider toward Green in the Color Balance dialog box. After you have corrected
the color cast in your image, the result is a relatively neutral image with accurate color.
However, just because you have achieved a neutral image with accurate color doesn’t mean you are finished with the Color Balance adjustment. In fact, even if you think the image has been adequately corrected with a single slider adjustment, adjust the other two sliders to see if you can’t produce a better result. Often you’ll find that by shifting the other sliders, you’ll produce an image with a more pleasing color balance than the neutral result you first achieved.
Note: In general, viewers respond more favorably to images with a warm color balance, so you may want to explore a shift toward warmer values (red, magenta, yellow). Looking again at our sample image, after producing a neutral result you might want to explore adding a shift toward warmer values. In this case, I applied a shift toward yellow to warm up the image and enhance the natural earth tones that were already present (see below). The result is an image with much greater warmth than the original adjustment produced.
After you’ve made adjustments to produce a neutral result, you can often
produce a better final image by making further adjustments. In particular,
adjustments that warm up the image slightly are often appealing.
Making Image Color Balance Adjustments in Photoshop
After you’ve adjusted all three sliders in the Color Balance dialog box, the basic process is complete. But keep going: move all three sliders again, this time making much smaller adjustments. Because each slider move affects all of the colors within the image, subsequent adjustments at least slightly alter the image; you might discover an even better result.
For the vast majority of images, all you need to do is adjust the sliders in the Color Balance dialog box after selecting the default Midtones setting in the Tone Balance section at the bottom of the dialog box. However, you can also change the range of tonal values within the image that will be affected by the Color Balance adjustment by selecting Shadows or Highlights and making separate adjustments targeted at those tonal ranges.
Each of these options for limiting the tonal values to be affected by the adjustment operates independently. When you select Shadows, for example, the adjustments you make will not replace or undo adjustments you made when the Midtones option was selected. The Midtones option will affect most values within the image, whereas Shadows and Highlights will limit the adjustment to the darkest and brightest values within the image, respectively.
Another option in the Color Balance dialog box is the Preserve Luminosity checkbox. With this option selected, when you adjust one slider the color values for the other channels within the image will be modified slightly so that the perceived luminosity of all colors is preserved. I recommend keeping this checkbox selected. The only time I recommend deselecting this option is when you are attempting to produce a perfect neutral value and want to be able to control each channel’s color value independently.
Hue/Saturation allows you to perform basic saturation adjustments.
In general, photographers want to boost the saturation of the colors in their images, so the most common adjustment is to increase the Saturation value. However, there are certainly plenty of situations where you might want to reduce saturation slightly. For example, if you are producing an image with a watercolor appearance, you’ll want to tone down the colors slightly so they don’t appear overpowering.
Although reducing saturation can be done to any degree based on your preference for how the image should look, a little more care should be taken when increasing saturation. If you increase the saturation too much, you can create some problems within the image. For one thing, the colors may start to look fake because they are too vibrant. Also, by shifting colors to their most saturated values, you are reducing the total number of possible values, and therefore increasing the risk of posterization in the highly saturated areas of the image. As a general rule, use caution when increasing the Saturation slider to a value above +20. That doesn’t mean you can’t increase Saturation further, just that you should carefully review the image to make sure you aren’t introducing any problems in doing so.
Other than exercising some care in how much you increase saturation, making an adjustment is really as simple as deciding how strong you want the effect to be. If your image doesn’t have very strong saturation (see below), you can easily produce a more pleasing image by increasing the Saturation slightly with a Hue/Saturation adjustment.
(left) When an image has colors lacking in vibrancy, the perception
is an image that is flat. (right) Boosting the Saturation adds life to the image.
Provided you are cautious not to apply an excessive boost in saturation, a basic increase in Saturation with the Hue/Saturation adjustment is one of the more straightforward adjustments you’ll make in a basic workflow for your images.
This article is adapted from Photoshop CS2 Workflow: The Digital Photographer's Guide (Sybex) by Tim Grey and is reproduced here with permission. Copyright 2005, Sybex.