Create Vector Masks from Photoshop CS5 Pen Paths
A layer mask covers areas of your Photoshop Creative Suites 5 image that you want to make transparent and exposes pixels that you want visible. Masks can be based on a selection you’ve created with the selection tools, by painting on the mask itself or by using the Pen tool to create a path around the object you want to keep visible (known as a vector mask).
A vector mask masks a selection, but it does so with the precision you can get only from using a path. The following steps show you another, slightly more precise, way to create a layer mask by using a pen path:
Use the Pen tool and click from point to point to make a closed pen path.
If you already have a path, choose Windows→Paths and click a path to select it.
On the Layers panel, click the Layer Mask button and then click it again.
Wow — a mask from your pen path! Anything not contained within the path is now masked out. Use the Direct Selection tool to edit the path, if necessary.Create a mask from your pen path.
If you no longer want a vector mask, drag the thumbnail to the Trash Can in the Layers panel. An Alert dialog box appears, asking whether you want to discard the mask or apply it. Click the Discard button to revert your image to the way it appeared before applying the mask or click the Apply button to apply the masked area.