The following is my technique for superimposing words onto a textured background in Photoshop. While there are probably numerous ways to do this, using Channels is a great way to use the texture of your background image to manipulate the text on top. Using channels is also a good way to create grunge effects on type or other graphic elements within a design.
1. Let’s begin with a background texture that we want to work with. In this case, we will use an image of a block of ice. You can find the original image here for the purposes of following this tutorial.
2. Convert the image to CMYK. IMAGE > MODE > CMYK COLOR
3. Import or create your text on a separate layer and rasterize the layer. TYPE > RASTERIZE TYPE LAYER
4. Hide the type layer so that you can make a channel selection of just the background ice image.
5. Activate the ‘Channels’ palette and flip through the channels, showing only one at a time. The grayscale values that you see represent the percentage of that channel’s colour.
6. Make a selection of one of the channels (in this example CYAN) by holding COMMAND and clicking on the layer in the ‘Channels Palette’.
7. Select the inverse of your new selection. SELECT > INVERSE
8. Activate all channels again by clicking on CMYK within the channels palette.
9. Unhide your type layer.
10. SELECT > TRANSFORM SELECTION to move your selection around and over top of your text.
11. Now that you have an active selection, you can use that selection to manipulate your artwork in a number of ways. Use an eraser tool or simply hit DELETE to remove color from the text layer. As an option, you can also use the selected area to paint a colour over top of your text with the brush tool. The results can be very cool! (intended pun)
12. Repeat steps 10-11 and move your selection to different parts of the type (here, I’d like to repeat the process at the top of the word ICY).
13. Done and done!