Tuesday, April 10, 2007

GIMP Tutorial: Creating Clipping Masks

The clipping mask feature is a quick way to create effects such as text filled with a photograph.

Clipping masks are commonly used in digital scrapbooking to create pages based on templates. While it’s an extremely easy task in Photoshop, it’s slightly more complicated to do in the GIMP, especially for a new user.

Because there is no "clipping mask" feature in the GIMP, we will use a modified technique to achieve the same effect. There are several ways to do this, but I found that using the "Alpha to Selection" tool was the easiest.

The following is from the GIMP User Manual: "The Alpha to Selection command creates a selection in the image from the active layer's alpha channel, which encodes transparency. Opaque areas are fully selected, transparent areas are unselected, and translucent areas are partially selected. This selection replaces the existing selection. The alpha channel itself is not changed."

While this may seem to be a complicated process, once you understand the steps, it's a fairly easy technique and extremely useful.

This technique will be demonstrated using a template created for digital scrapbook layouts; however, it can be applied to a range of activities.

1. Open the template (most likely a .psd file) in the GIMP.

2. Open your layers dialog: Dialogs-->Layers or F7

3. Select the layer containing the image you want to replace (hereafter called "template layer"). In this example, we'll select paper1.

4. Open as a layer (File-->Open as Layer) the image that contains the pattern that will be replacing the template layer. Move this layer (hereafter called "image layer") directly above the template layer.

5. Right-click on the template layer and select "Alpha to Selection."

6. In the Layers dialog box, select the image layer. Then copy (ctrl+c) and paste (ctrl+v).

7. Make your floating selection (the result of pasting) a new layer by right-clicking on the "Floating Selection" layer in the Layers dialog box and selecting "New Layer" (alternatively, you can simply click the paper icon at the bottom left of the layers dialog box).

8. Move the pasted layer directly over the template layer. Delete the original image layer (i.e. the full-sized image that contained the pattern).

9. Merge the Pasted Layer down into the template layer.

And you're done!

Template by Dumpty; Paper from "Her Day Out" by Sweet Shoppe Designs
Italy image from saulgoode at GIMPTalk