Rangefinder Magazine
November 2004

Photoshop CS by Dave Cross
The Power of Adjustment Layers

This article focuses on one of the most flexible techniques in Photoshop®: Adjustment Layers. As you’ll see, you can use Adjustment Layers for a variety of purposes, all of which offer incredible control and flexibility.

Why should you use Adjustment Layers?
Let’s pretend for a moment that you just came in from the bright sunny outdoors and immediately started adjusting an image (even though your eyes were a little “out of whack”). You open your image and use the Levels command (Image > Adjustments > Levels) to lighten the image. Unfortunately, your adjustment was a little overboard, but because you’re not really seeing properly, you don’t realize this, and you click OK to save the document.

Next day, you open the image and see that your adjustment was a little much, so you try the Levels command again. Looking at the histogram (shown in image), you realize it’s going to be next to impossible to undo your original adjustment. As we’ll see, an Adjustment Layer would allow you to make further adjustments, including putting the image back the way it started. Hopefully, you won’t ever make this kind of mistake, but it does underline the potential problem of using the adjustment commands found under Image > Adjustments: They’re pretty much permanent changes.

Adjustment Layers to the Rescue
Instead of using the Image > Adjustments menu, try using the pop-up Adjustment Layer menu at the bottom of the Layers palette. In this example we’ll add a Levels Adjustment Layer. Use the dialog box in the normal manner, but when you click OK you’ll see that a separate layer is added that contains the adjustment.

Even if we were to make an over-adjustment as in the scenario above, we can easily fix it by double-clicking on the layer thumbnail in the Layers palette and making adjustments in the dialog box. In addition, after saving the file (as a PSD), you always have access to the Adjustment Layer simply by double-clicking on it. (Or, you can hide the layer, or delete it, and start over!)

Partial Adjustments
One of the added benefits of Adjustment Layers is the ability to show and hide portions of the adjustment by painting on the accompanying Mask. In this example, we clicked on the Adjustment Layer in the Layers palette in the lightened image and painted with black wherever we didn’t want the adjustment to take effect. By painting with black over the couple in the photo, we’re able to hide the Adjustment Layer in that area and make the rest of the image look lighter. If you change your mind, just paint using white to activate the effects of the Adjustment Layer.

Colorizing
Here’s another great advantage of using Adjustment Layers: colorizing an image. By adding a Hue/Saturation Adjustment Layer and turning on the Colorize box in the Hue/Saturation dialog box, we can experiment with the sliders to affect the images. Use the Hue slider to change the color, the Saturation slider to affect the intensity of the color, and the Lightness slider to alter the brightness. As before, you can double-click on the Hue/Saturation layer thumbnail in the Layers palette to change the color, or paint with black to hide the effects of the colorization.

Note: If you select an area before adding the Hue/Saturation layer, only that area will be affected.

Limiting the Effects

By nature, an Adjustment Layer affects all layers below it, so what do you do if you only want the adjustment to influence one specific layer? You have a couple of options, depending on the position of the layer you want to affect. If the layer is at the bottom of the layers stack then you can add an Adjustment Layer and only that one layer will be affected. If, however, your layer is not at the bottom, you’ll have to use either a layer Clipping Group or a Set.

In this example, we’ve created a simple wedding photographer’s collage (using layer masks for increased flexibility). If we were to add a Hue/Saturation layer at the top of the layer stack, all layers would be colorized To force the Adjustment Layer to affect only the layer immediately below it, press Cmd G (Ctrl G on a PC) or use the menu command Layer > Group with Previous. Now, only one layer is affected by the Hue/Saturation layer. To undo, press Cmd Shift G (Ctrl Shift G) or choose Layer > Ungroup.

If you need the Adjustment Layer to affect some but not all of your layers, try using a Set. Click to the left of the layers you want to be affected to link them all together. From the Layers pop-up menu, choose New Set from Linked. In the dialog box, change the mode from Pass Through to Normal. If necessary, move the Adjustment Layer within the Set until it’s at the top of the layers in the Set. All the layers in the Set will be affected by the Adjustment Layer, but the Background (and any new layers that aren’t put in the Set) are not influenced by the Hue/Saturation layer.

There are many techniques you can use to give yourself the opportunity to change your mind. Once you’ve used an Adjustment Layer, chances are that this technique will move to the top of your list of flexible work habits.

Dave Cross is Senior Developer, Education and Curriculum for NAPP (National Association of Photoshop Professionals) and co-author of three books: Photoshop 7 & Illustrator 10: Create Great Advanced Graphics, Photoshop 7 Trade Secrets, and Adobe Illustrator Killer Tips. Dave is also one of the lead instructors for NAPP’s Adobe Photoshop Seminar Tour.

This is one of a series of Adobe® Photoshop® tutorials sponsored by Adobe Systems and the National Association of Photoshop Professionals (NAPP) to be reprinted in Rangefinder taken from the Photoshop User magazine, the official publication of NAPP (www.photoshopuser.com).