We often perceive color in digital photos to be “correct” when the neutral tones – if they exist – are indeed neutral. But in the real world, light always has some color cast or other that affects the areas it illuminates. A camera sensor ruthlessly reproduces these uninvited hues, but still, we try to edit photos to reflect our own vision. Gradient maps can either correct color or spin it to your advantage.
You can use gradient maps for dramatic black and white conversions or create different monochromatic effects, but this article focuses on color gradient maps to:
- Use them to subtly improve photos
- Separate elements within your compositions using color contrast
- Make subjects stand out
What does a gradient map do?
A gradient map at its simplest is a smooth gradation between one color (or tone) and another. Let’s say you have a gradient map that goes from green to orange. When you apply that to an image, the shadows would have a green tint and highlights an orange one. The mid-tones are typically least affected except with more complex multi-color maps.
You might be wondering at this point: why would I want to twist the color of a photo and effectively give shadows and highlights a color cast? This, after all, is virtually the opposite of a white balance correction. One reason is to enrich the colors that already exist in a photo.
Another good reason to use gradient maps is to harness the power of complementary or analogous colors and create more eye-catching pictures. Sometimes, the feel of a photo is more important than the truth, which only ever exists in degrees to begin with.
If you imbue your shadows and highlights with complementary colors, you will often make the photo a little more eye-catching. It might be subtle, but it still works in your favor. This isn’t a magic bullet that makes all photos great, but it’s fun to experiment with. You’re becoming a colorist.
Creating gradient maps
The simplest way to create a gradient map in Photoshop is to go to your toolbar and set the background and foreground colors to the ones you want at either end of your gradient. Then, when you open the gradient map, the colors are already in place.
If you want to use precise colors in your gradient map – perhaps complementary colors you’ve found on the Internet – you can enter the hex numbers into the color picker pane instead of randomly sampling.
This is one method for creating a gradient map:
- Open your image in Photoshop.
- Go to the toolbar and set the background color (click on the rear of the two squares to bring up the color picker pane). This will be your highlight color, bearing in mind you can reverse the gradient in Photoshop anyway.
- Do the same with the foreground color by clicking on the front square. This will be your shadow color.
- With the shadow/highlight gradient colors chosen, open a gradient map adjustment layer. At this point, the photo looks drowned by color, but we’re not done yet.
- Choose either soft light or overlay blending modes and adjust the opacity to taste.
Needless to say, not all gradient maps suit all pictures. One way to create useful gradient maps is by looking for color schemes on the Internet. There are also websites that discuss the color palettes used in movies or movie scenes, which you can “borrow” for your own photos.
A more tailored way to create a gradient map is as follows:
- Open your image in Photoshop.
- Open a gradient map adjustment layer.
- Set the blending mode to soft light or overlay.
- Click on the gradient to open the gradient editor.
- Click on the left color stop (square slider at lower left), then click in the color window that activates.
- At this point, you can adjust the shadow color and see its effect in real time on your photo as you move the color picker around.
- Do the same with the right-hand highlight color stop.
- Now you have a custom-made gradient map for that image.
Note: you have to use the preset manager in Photoshop to save your gradient maps if you want to use them again. Otherwise, they vanish when you close the program.
Gradient maps vs color LUTs
An alternative to gradient maps is color LUTs (look-up tables), which you can also find in Photoshop and other programs. Rather than applying color according to the tone of the image as a gradient map does, a LUT shifts hues numerically.
The latter often causes a radical change in mid-tone subjects like skies and trees, whereas simpler gradients tend to leave those areas relatively unscathed. But it depends. LUTs, like gradients, vary a lot in their effect.
The starting point: white balance
Whether you apply a gradient map or a LUT, the end result is affected by the preexisting white balance in the image. As photographers, we don’t always want to drain a photo of warm or cold light with a white balance adjustment. It’s frequently this light that makes the picture – adds to its atmosphere. However, such an adjustment ensures a purer result with gradient maps and LUTs.
Color LUTs and gradients are usually designed from a white-balance-corrected starting point. So, if you want to see them as the author intended, consider correcting white balance at the raw stage. This isn’t anywhere near compulsory: you can simply lay these edits over photos and they’ll act as filters. Just know that their effect can be exaggerated, skewed or diminished if the photo already has a color cast.
If you customize a gradient map to suit the image, the need for a prior white-balance adjustment obviously disappears. But this is time consuming compared to having a set of tried-and-tested presets at your fingertips.
Creating multi-color gradient maps
I find simple two-tone gradient maps more useful and certainly more versatile than complex ones, but you can add further colors to the gradient if you wish. You might add a separate color to mid-tones, for instance.
Use analogous colors (sets of three closely related hues) or triadic colors to inspire you, or customize a gradient to enhance the colors that exist in a photo.
Here’s the method for adding a further color to your gradient:
- Open your image in Photoshop.
- Create a two-color gradient map as above (steps 1-7).
- Click under the center of the gradient in the gradient editor to create a third color stop.
- Click on the newly created color stop to activate the color window, then click in that window.
- Choose a third color that complements the image (e.g. for mid-tones) and adjust its effect by changing the position of the middle slider. The small outer sliders alter the area affected by this color regardless of its position along the tonal range.
The more colors you add, generally the muddier and less “realistic” the photo appears, but that may be an effect you’re going for.
You can add gradient maps to photos and many people won’t notice you’ve done it. But that’s not to say they don’t have the desired effect.
Just like in the movies, you’re using color to create a mood or make the subject or foreground stand out from the background. You’re not necessarily trying to draw attention to the color itself, even if it pleases your eye.
Many photographers think in terms of light and dark to create impact, or saturation boosts, but color contrast is a rarer consideration.
Although gradient maps (and color LUTs) are powerful tools for making pictures stand out, it’s easy to get carried away with them. After a period of overdosing, you’ll come to recognize the types of images they work best on and which of your gradients to use where. Here are five free gradients you might like to try out. Happy colorizing!
Try out these techniques and share your images with us in the comments below.