Tutorial: Photoshop Clipping Masks -07/09/07
Clipping masks are one of my favorite Photoshop features. Learn to apply textures or images to an area quickly and easily.
Clipping masks are a fantastic way to add texture and depth to objects. This tutorial will use clipping masks to create a button with a brushed metal surface. This is just a sample to demonstrate how you can use this technique, but clipping masks are useful for all kinds of effects.

Start with a new file and fill the background with a dark grey.
Tip
[ALT+DELETE] will fill the layer with the foreground color and [CTRL+DELETE] will fill the layer with the background color.
Create a new layer. Use the marquee tool to draw a circle and fill it with color. I used a bright blue. (You can use the same shortcut to fill your selection.)
Now we're going to create the brushed texture.
Create a third layer and fill it with black (wow, that fill shortcut is pretty handy).
Go to Filter>Noise>Add Noise. Turn the amount all the way up to 400% and make sure the 'Monochromatic' option is checked before applying the filter.

Here comes that brushed texture.
Select the Noise layer and go to Filter>Blur>Motion Blur.
Adjust the amount until it looks right to you. The number will vary depending on the size of your image. If you want to make the effect more dramatic you can increase the contrast on this layer.
Change the layer effect to 'Overlay'.
Now it looks like the whole image has a brushed metal texture, but we only want the circle to have this effect.Here comes the magic.
Hold down [ALT] and hold the cursor between the layers with the noise and the circle. You will see your cursor change to a little double circle icon. Click between the layers.
Tip
You can also apply the Clipping Mask from the menu. Select the layer you want to become a mask and go to Layer>Create Clipping Mask.
Voila! A clipping mask! It's still a little plain, so let's add some more.
Tip
You can create straight lines with your brush tool by using [SHIFT]. Chose your brush tool and click a point. Then hold down the {SHIFT] key and select another point. This will paint a straight line between the two points.
Change the layer effect to 'Soft Light' to make the shadows blend into the object.

I added a couple of layer effects as a final touch. I used 'Drop Shadow' and 'Bevel and Emboss' to give the button a little depth. That's all there is to it!
Here are some more samples of what can be done with clipping masks.

I did a little self portrait in the style of those new Paul McCartney iPod commercials. I posterized a black and white photo of myself and deleted the white areas so only the black parts of the photo would have the effect on it. I created another layer with a blue and pink gradient and created a splotchy purple brush to paint the middle area. I clipped those layers together and created a nice watercolor effect.
Clipping masks are also great for laying photos over text. I used a photo I took of some graffiti in Israel for the image above. I copied the photo to a second layer and decreased the brightness on the bottom layer for the background. I left the layer copy on the top to use as my mask. I made a new layer with the type in between these layers and clipped the type and the top layer together. I adjusted the mask layer until I found a spot that I thought looked alright. I can continue to edit the type and the mask layer separately without destroying either. This flexibility is what makes clipping paths so powerful.