Photoshop tip: See layer mask only

If you work with a layer mask in Photoshop, it is sometimes difficult to see if you really masked all the areas that should be masked. Here is quick way to check the mask and edit it if needed: Alt-click on the mask icon in the Layer palette. You will now see the mask only, as a black and white image. This allows you to inspect the mask itself, and to edit it where needed. Click on the mask again (without the key) to go back to the normal mode where you see the image rather than the mask.