The Photoshop Tip of the Week for the Clients and Friends of Ben Willmore (www.digitalmastery.com):

This week we're going to explore one of my favorite features in Photoshop-Layer Masks. For those of you who haven't ventured into the land of Layer Masks, take heed, because once you've used them (and taken the time to get friendly with them), you'll discover that Layer Masks can be one of your greatest companions in Photoshop.

A Layer Mask is a grayscale image that is attached to a layer (I'll show you how to create one in a moment). In a Layer Mask, white areas leave the layer alone and black areas temporarily hide an area. It's just like using the Eraser tool, but a million times better, because the changes you make aren't permanent until you decide to make them permanent. And, as long as you save your image in the Photoshop file format (psd), you can open that file a month later and undo the change you created by simply deleting the Layer Mask.

To add a Layer Mask to a layer, choose Layer>Add Layer Mask>Reveal All, or click the left-most icon (5.5) or second from the left icon (6.0) at the bottom of the Layers palette.

Once you've added a Layer Mask, you can type D to reset your foreground/background colors, and then use the Eraser tool to hide areas, or use a painting tool to bring back areas that have been hidden. You can use soft-edged brushes to create a smooth transition between the areas that are hidden and the areas that are visible.

If you'd like to edit the contents of a layer (instead of the Layer Mask), then click the thumbnail preview image (in the Layers palette) to make that layer active. To switch back to editing the Layer Mask, click the Layer Mask thumbnail preview image.

Now let's look at a few tips related to Layer Masks:

If you hold Option (Mac), or Alt (Windows) when clicking the Layer Mask icon, Photoshop will hide the content of the current layer by filling the Layer Mask with black.

If you have a selection active when clicking the Layer Mask icon, Photoshop will hide the non-selected areas by filling those areas with black in the Layer Mask. If you Option-click (Mac), or Alt-click (Windows) the Layer Mask icon when a selection is active, then Photoshop will hide the selected area.

Type Command-~ (Mac), or Ctrl-~ (Windows) to make the main image active instead of the Layer Mask (the tilde key (~) is located near the 1 key on your keyboard). Type Command-\, or Ctrl-\ (Windows) to make the Layer Mask active.

If you'd like to remove a Layer Mask, then drag its thumbnail preview image to the trashcan at the bottom of the Layers palette. When you do that, you'll be prompted to either discard (bring back the hidden areas), cancel (don't remove the Layer Mask), or apply (delete the areas that are hidden) the Layer Mask. When that dialog box appears, typing the first letter of any of the buttons will do the same as clicking them.

To view the contents of a Layer Mask in the main image window, Option-click (Mac), or Alt-Click (Windows) on the Layer Mask preview thumbnail image in the Layers palette. To view the Layer Mask as a colored overlay, Option-Shift-click (Mac), or Alt-Shift-Click (Windows) on the Layer Mask preview thumbnail image or type \.

In order to paste an image into a Layer Mask, the Layer Mask must be visible. A quick method is to make sure the Layer Mask is active, then type \, choose Edit>Paste, and then type \ again.

To copy a Layer Mask from one layer to another, make sure the layer you'd like to apply it to is active (and doesn't have a Layer Mask attached to it yet), then drag the Layer Mask thumbnail preview image from another layer onto the Layer Mask icon at the bottom of the Layers palette. Remember, to make this work, the layer you'd like to apply the mask to must be active.

If you decide to use the Gradient tool in a Layer Mask, you'll most likely want to use the Foreground to Transparent setting so that the gradient adds to the existing content of the mask instead of replacing the content.

Don't limit yourself to the Paintbrush or Gradient tool when working with Layer Masks. Any tools that work on a grayscale document will work on a Layer Mask, so start applying filters and adjusting your masks with all of Photoshop's features. There truly is no limit to what you can do with a Layer Mask.

Until next week, have fun Photoshopping.

-Ben Willmore