Clipping Mask (updated for CS4)
1. Clipping masks is a feature in Illustrator that enables you to mask out an image that you placed within the Illustrator document. With this example, I am going to use the type layer as my masking layer. First off, I want to place an image on my Illustrator document. To place a document efficiently in Illustrator, go to FILE > PLACE. Look for the image you want to place on your computer. (not cut and paste from photoshop or other photo programs).
2. Make sure you don’t outline the font cause it’s really not necessary to do so. Now let’s apply the mask. Make sure you have both the letters and the background imagery selected at once.
3. Now go to OBJECT > CLIPPING MASK > MAKE. That’s it!
4. The result so far. You can see the photo in the back through your letters.
5. Now remember I told you not to outline your fonts? Well here’s the reason why. You can STILL edit your text after you applied the mask as you can see here. The same goes for shapes and patterns. You can still go back and change them after the mask has been applied. And also another thing you can do is get the white arrow tool and move the letter around while the background stays in a static position! So you can move it around to see where you want to make the clipping mask first. This is great with shapes such as circle and squares (and not text like this tutorial).
6. Now what happens if you did OUTLINE the font? Well you can also play around with the anchor points of the text and manipulate the font while the background image still follows the clipping mask.