How to Use Complementary Colors in Photoshop

Complementary colors, the pairs sitting directly opposite each other on the color wheel, almost always look good together, which makes them a reliable way to color-grade a background so it plays off your subject rather than fighting with it. Rather than guessing at a color that “looks about right,” Photoshop’s Adobe Color Themes panel can calculate the exact complementary color for you. In this tutorial we’ll sample the color of a subject’s hat, find its true complement, and use that color to recolor the background of the photo, masking it so only the background is affected.

What Are Complementary Colors?

On a standard color wheel, complementary colors sit at exact opposite points from each other. Pairing them tends to create a pleasing, high-contrast harmony, which is why you’ll see this relationship used constantly in film color grading, poster design, and photo editing. The challenge is precision, eyeballing a “roughly opposite” color rarely gives you the same clean result as calculating it directly from the actual color in your image.

Loading the Adobe Color Themes Panel

Go to Window > Extensions > Adobe Color Themes to open the panel. This dialog can generate several types of color relationships from a single starting color, including Analogous, Monochromatic, Triad, Complementary, Compound, and Shades. Selecting Complementary is what gives you the precise opposite-wheel color pairing this technique relies on.

Sampling Your Base Color with the Eyedropper

Select the Eyedropper Tool and click on the color in your photo you want to build a theme from, in this case, a subject’s hat.

Increasing the Sample Size for Accuracy

By default the Eyedropper reads a single pixel, which can vary wildly depending on exactly where you click. In the options bar, change the Sample Size from Point Sample to 31 by 31 Average, which reads a larger area and averages it together for a much more representative color. Click on the hat again with this larger sample size active to load a reliable, accurate color as your active color.

Finding Your Complementary Color

Back in the Adobe Color Themes panel, click the middle icon beneath the color wheel labeled “Set selected color from active color.” This loads your sampled hat color into the panel’s central swatch. Now click through the color harmony options; Complementary will show you a set of shades built from the color sitting directly opposite your hat color on the wheel. This becomes the color you’ll use to recolor the background.

Reading a Color’s HSB Values

Clicking any swatch in the Color Themes panel reveals its numeric breakdown in several formats: CMYK, RGB, Lab, HSB (Hue, Saturation, Brightness), and a hex code. HSB is the most useful format for this technique, since Hue is really the value that determines whether a color reads as complementary; you can carry that Hue number forward into other Photoshop dialogs even if you adjust saturation or brightness later.

Method 1: A Solid Color Fill Layer

Click your complementary color swatch, then click the leftmost icon in the panel labeled “Click to set active color,” which loads that color as your foreground color. Go to Layer > New Fill Layer > Solid Color; the dialog automatically loads your foreground color as the fill. Change that fill layer’s blend mode from Normal to Color so it tints the image beneath it using the fill color’s hue and saturation rather than replacing it outright.

Method 2: A Colorize Hue/Saturation Layer

A second approach uses the Hue value you noted earlier. Go to Layer > New Adjustment Layer > Hue/Saturation, check the Colorize box, and type your complementary color’s Hue value directly into the Hue field. This applies a single, uniform hue across the whole image, and you can raise or lower Saturation afterward to taste, though pushing saturation too high tends to look unnatural quickly. Comparing this method against the solid color fill layer lets you choose whichever level of saturation looks best for your image, and you can always come back and adjust it further since it’s a fully editable adjustment layer.

Masking the Color to Just the Background

Whichever coloring method you choose, right now it’s affecting the entire image, including your subject. To fix that, you need a mask that isolates just the background.

Selecting the Background with Color Range

Create a new layer, then go to Select > Color Range. Click on the background with the eyedropper to sample its color range, and use the plus eyedropper to add any additional background tones the first click missed. Adjust the Fuzziness to find a balance if the selection is picking up too much of your subject’s clothing or skin, since some background colors may be close to colors elsewhere in the photo. Click OK once the selection looks like it’s grabbing mostly background and minimal subject.

Cleaning Up the Mask and Copying It to the Other Layer

With your Color Range selection active, click your color layer’s mask thumbnail and press Ctrl+I (Cmd+I on Mac) to invert the mask inside the selection. That gives the opposite of what you want, so deselect with Ctrl+D (Cmd+D on Mac) and press Ctrl+I (Cmd+I on Mac) once more; now the color shows on the background rather than the subject. Grab the Brush Tool and paint white on the mask over any background the selection missed, filling in around the hair. Once this mask looks right, hold Alt (Option on Mac) and drag it from this layer’s mask thumbnail onto your other color layer’s mask thumbnail to copy the exact same mask across, so both the fill layer and the Hue/Saturation layer are masked identically.

Why This Approach Works

This technique works because it replaces guesswork with an actual color-theory calculation. By sampling the exact color already present in the photo and letting the Adobe Color Themes panel calculate its true opposite on the color wheel, you guarantee the new background color and the existing subject color are genuinely complementary, not just approximately close. Using Color Range to build the mask, rather than manually selecting the background by hand, keeps the effect confined to only the pixels that actually need it, and building it as an adjustment or fill layer rather than a direct edit means you can revisit the hue, saturation, or mask at any point without starting over.

Final Thoughts

Complementary colors are one of the most dependable relationships in color theory, and Photoshop’s Adobe Color Themes panel takes all the guesswork out of finding them. Sample a color already present in your photo, generate its complement, apply that color with either a solid fill or a colorize Hue/Saturation layer, and mask it to just the area you want changed using Color Range. The result is a background that feels intentionally designed to complement your subject, because it mathematically is.

Quick Reference: Keys, Menus and Settings

• Open the panelWindow > Extensions > Adobe Color Themes
• Sample the colorEyedropper Tool, Sample Size: 31 by 31 Average, click the hat
• Find the complementMiddle icon: Set selected color from active color, then Complementary
• Solid colorLeftmost icon to set the active color; Layer > New Fill Layer > Solid Color, blend mode Color
• ColorizeLayer > New Adjustment Layer > Hue/Saturation, Colorize, Hue 159
• Mask the backgroundSelect > Color Range, plus eyedropper, Fuzziness; Cmd/Ctrl + I inverts, Cmd/Ctrl + D deselects
• Copy the maskAlt/Option-drag the mask onto the other color layer

No AI, no generative credits.