Adjustment Layers are a special kind of Photoshop layer. Rather than having content of their own, they adjust the information on the layers below them. For example, you can use an adjustment layer to increase the brightness or contrast of a photograph without altering the original photo. They’re one of the most important tools to master in Photoshop.
If you aren’t familiar with layers and layer masks, be sure to check out our explainer on the subject–and if you’re new to Photoshop, you should also check out our 8-part beginner’s guide before continuing.
Non-Destructive Editing: One of the Most Important Photoshop Concepts You Can Learn
When you’re working in Photoshop, it’s never good to manipulate the pixels in the original image. If you mess up, you might not be able to undo things. Instead, you want to use non-destructive tools and techniques. Adjustment layers are one of these tools. They alter the image below, but you can always turn them off or modify them, so your original image stays untouched. You aren’t stuck with what you’ve done.
For example: if you destructively convert an image to black and white, you’re throwing away all the color information. You aren’t able to go back and change it back to color if you save the file. If you use the Black and White adjustment layer, though, you can go in at any stage and adjust how each color is converted to gray—or turn off the layer entirely to get your color image back. (This is also why backups are important for any mission-critical files.)
The Five Basic Adjustment Layers (and How to Use Them)
To use an adjustment layer, click on its icon in the Adjustment Layers panel. You can then dial in the effect you want in the Properties panel. The controls for each adjustment layer are different and specific to its purpose.
Each adjustment layer automatically comes with a layer mask. That way, you can have it affect certain areas of your image instead of the entire thing.
Photoshop has 16 different adjustment layers. However, if you’re just staring out, there are only five you need to be familiar with. As you get into more advanced Photoshop work, you’ll learn to use the other ten.
The Brightness/Contrast adjustment layer is the simplest way to adjust the exposure or contrast of an image. Drag the Brightness slider to the right to brighten things, drag it to the left to darken things. It’s the same for the Contrast slider: drag it to the right to add contrast, drag it to the left to take it away.
The Levels adjustment layer is another way to adjust exposure and contrast. The histogram represents all the tones in the image.
Drag the black handle under the histogram to the right to darken your image. Drag the white handle to the left to brighten it. The gray handle controls the midtones: drag it to the left to brighten the midtones, and drag it to the right to darken them.
There are a few more advanced options with Levels but, when you’re starting out, you don’t need to worry about them. Just play around with the sliders to achieve the effect you want.
The Curves adjustment layer is the most powerful (and advanced) way to modify exposure and contrast. It’s a bit beyond most beginners, however it’ll frequently pop up in Photoshop tutorials, so it’s worth knowing.
The sloped line over the histogram represents the current tones in the image. Changing the slope of the line determines how each group of tones is affected.
Click anywhere on the slope to add a point. Drag the point up to brighten the corresponding tones; down to darken them. You can add as many points as you need. By manipulating which points you drag up, and which you drag down, you can add contrast to the image.
Again, this tool is very advanced, but there’s a lot you can do with it–you’ll see it in a lot of Photoshop tutorials around the web. Check out our explainer on histrograms for a more in-depth look on how it all works.
The Hue/Saturation adjustment layer is a simple way to adjust the colors in your image. Every color has a hue, saturation, and lightness value. The Hue/Saturation adjustment layer’s sliders correspond to them. Drag the relevant slider around to manipulate that aspect of the colors.
By default, you’re editing all the colors as a whole. From the dropdown where it says Master, you can select any of Photoshop’s six primary colors—the Reds, Yellows, Greens, Cyans, Blues, and Magentas—to modify on their own. With this, you can achieve all sorts of different effects.
Black & White
The Black & White adjustment layer is the best way to convert an image to black and white. It has six sliders: one for each of Photoshop’s primary colors. Each slider controls how that color is converted into grayscale. Drag the relevant slider to the right to darken those colors; drag it to the left to brighten them.
Adjustment layers are the best way to modify the tones and colors in your images. But most importantly: they don’t change the original pixels so you can always go back in and tweak things. Some adjustment layers, like Curves, can be a bit tricky to get to grips with but it’s worth the effort. They’re a huge part of most Photoshop work.