The "Origin of the Species - wall hanging" project makes a nice use of opacity masks in Illustrator, embedding an image in a field of text by changing the opacity throughout. But pulling this off can be difficult to figure out. This guide will run you through the steps to embed an image in a field of text merely by changing the opacity of the text itself. In this example, a silhoutted image is embedded in the full text of Romeo and Juliet.
Step 1: Gather your image and text
This guide will use a stripped down example because the actual sizes of text and images involved in a fullsize wall hanging will grind your system down to a crawl. You should experiment on a small scale before committing to a fullsize design.
*Obtain an image (it should be something that would look good as a silhouette)
*Obtain the text (Project Gutenberg is a great resource) and format out all the newlines and other whitespace (see the "Book Wall Hangings - Flatlands - cube" project for more info on this...)
I used the text of Romeo and Juliet with an image of Leonardo di Caprio and Claire Danes from the movie Romeo+Juliet.
Step 2: Process your image
Basically you must turn the image into a silhouette. In Photoshop you can go to Image--Adjustments--Threshold and drag the slider until you achieve satisfactory results.