This is one of over 4598 effects generated by Filter Forge, a Photoshop plugin that allows you to create your own filters.
This effect:
Download Filter Forge to use this effect
To open this filter, you must have Filter Forge 1.0 or higher installed on your computer. If you don't have it installed yet, click here to download Filter Forge
Just a simple way to highlight or shadow from any side of an image.
Craig Kraellin Walters side shadow highlight mask darken lighten