Building Accurate Adjustment Layer Masks
By Dan Moughamian, © 2009

Web Reproduction Rights Granted to geofflawrence.com

Introduction

An important task when enhancing your digital pictures with Photoshop CS4, is creating layer masks to isolate your edits.  For example, layer masks are a great way to ensure that your adjustment layers are affecting only a specific group of tones and colors in the image. This tutorial explains a new capability in Photoshop CS4, that allows you to generate an accurate layer mask without closing your adjustment layer first. Using a combination of the new Adjustments panel and Masks panel, and an improved Color Range function, you can quickly target your adjustments to very specific regions of the image.

Cool Waters, Cool Sky

For this example, I’ve opened an image and applied a modest amount of color and tonal correction, as well as a bit of noise suppression and sharpening in Adobe Camera Raw. Once in Photoshop I began to make addition edits, and in this case, one of the first things I saw was a need to enhance the sky a little bit, and take away some of the faint, gray-green haze near the horizon and generally make things a bit cooler in temperature. For this image I used a Photo Filter adjustment (Cooling 80).

However the problem that arises, is that by default, the cooling filter is applied to the entire image, not just the sky (or just the sky and water, which would be OK too). To remedy this, we can use the adjustment layer’s built-in mask and the new Masks panel options to generate a mask based on the color of the sky and/or water.

Steps

Once your adjustment layer is created, click on the Masks panel tab, then click the Color Range button, as seen in Figure 2. This will open the same Color Range dialog which you can access from the Select menu. There are many different workflows you can use to generate and preview the mask, but I typically set the in-dialog preview to show the “Selection” so that I can actually see the complete grayscale representation of the mask at all times.

I also ensure the Selection Preview menu is set to “Black Matte” for most images. This enables me to quickly evaluate what’s being selected and what is being masked on the document itself. For darker images, I use “White Matte”, since Black Matte wouldn't provide much visual contrast in that case.

Once your preview options are set, use the eyedropper to shift-click on the general regions of the image you wish to select (i.e. not mask away). As you do so, more of the image will be revealed from under the black mask, and the grayscale preview in the dialog will update with each click. For this example I clicked in several sky locations and on a few of the clouds to make sure they weren't masked. The result prior to generating the actual layer mask can be seen in Figure 3.

If the regions of color you’d like to select are all adjoining and you specifically do not wish to include other regions of the same color from your picture, click on the Localized Color Clusters option, using the Fuzziness slider to determine how strict the Color Range function is in limiting your selection to the localized area you've chosen with the eyedropper.

Once you’re ready to apply the actual mask to your adjustment layer, just click OK. Now, notice that the adjustment layer you’ve created has a detailed layer mask to the right of the layer thumbnail. That’s all there is to it! The final result can be seen in Figure 4, with the sky and water now a much more pleasing shade of blue, while the coral and rocks in the foreground have lost none of their warmth. This provides a nice color contrast between warm and cool shades. I’ve also added a Radial blur around the periphery of the image for a bit of fun and added effect (that’s what Photoshop is for, after all).

©2009, Dan Moughamian

Dan Moughamian is a professional photographer, instructor and the co-author of Real World Compositing with Adobe Photoshop CS4(Peachpit, Adobe Press). You can read more about his work at Colortrails.com.

Photoshop Tutorial	Description	Level
Size	Scaling your files.
Contrast	Balancing those pixels.
Colour	Dealing with colour casts.
Levels	A short video showing how to use the levels adjustment to control contrast.
Processing RAW Files	An introduction to Adobe Camera Raw.
Processing RAW Files using HSL	Advanced use of ACR.
Sharpening	Using the unsharp mask.
Using the Quick Mask	Masking parts of your picture to edit certain areas.
Adjustment Layer Masks	How to build accurate layer masks.
Straightening Horizons	A must for landscape and building photographers.
Replacing Boring Skies	Using layers in Photoshop.
Videos on Compositing	Video tutorials on using layers.
Using the Channel Mixer	How to make a better job of changing images from colour to black & white.
Using Curves on Adjustment Layers	laying with contrast and tones to give a more dramatic effect.
High Dynamic Range	How to shoot and process HDR pictures with Photomatix Pro software.