How can I create a ragged edge on a box with an image mask in Illustrator?

Question

I apologize if the title of the question isn't terribly clear, I'm struggling with finding terminology that is adequate.

Essentially, what I am trying to do is create a rectangle that looks like a piece of old paper that has torn edges at the top and the bottom, as though it was torn off a roll. Here's how I've tried to accomplish this:

• I created a rectangle
• I placed an "old paper" image behind the rectangle
• I created an image mask with the rectangle and image
• I hand drew a line with the pencil and used the wrinkle tool to make it jagged; I drew the line such that it crosses the entire width of the visible rectangle and it sometimes breaks the top edge of the rectangle as well
• I'm using Pathfinder's "Minus Front"

What ends up happening, I think, is that the image mask is deleted and I'm left with a jagged line and an image. How can I get the effect I'm going for?

(In case it's important, I need the final object to be one object so I that I can duplicated it and create a drop shadow.)

Answer 1

You can simply draw a line and use Effect > Distort & Transform > Roughen to create a jagged line.

Then copy the line, select both the "rough" lines and choose Object > Expand Appearance. Then select the end points and join them via Object > Path > Join. It's important to draw a separate line and apply the effect to just a line if you don't want all 4 sides of a rectangle to be "roughened". This method is specifically set up to provide 2 straight sides and 2 rough sides.

If you really want to use a raster image you need to use an Opacity Mask and things need to be stacked correctly first - a rectangle or shape object, on top of that place the raster image. Select the raster and the object below it and on the Transparency Panel click the Make Mask button. You may need to then tick the "Clip" and/or "Invert" options on the Transparency panel.

Pathfinder does not function with raster images. Realize that even as a mask, a raster image is still bound by all standard raster constraints. Simply because you are using Illustrator, it does not make raster images impervious to broken pixels or other resolution issues when the raster images (or masks) are scaled.

Update

A clipping mask..... If you just want to mask a raster image with a vector shape. Place the vector shape above the raster image, select the raster and the shape, then choose Object > Clipping Mask > Make from the menu. This will essentially give you the raster image inside the vector shape.