I'm going to show how to float a product and shadow off it's original background. I'll be working on a Mac and using keyboard shortcuts. Have no fear PC users, your keyboard shortcuts will also be posted. There will be images to go along with the lesson. Remember to click on the pics to make them larger. Let's get started...
1. Start with a flattened image with a path around the product.
3. In the Layers Panel, turn selection into a layer. (Command J for Mac/Control J for PC)
5. Go to the Channels Panel. Command click (Control click for PC) the RGB channel and turn it into a selection.
6. Double click the Quick Mask icon at the bottom of the Toolbar. This will open up the Quick Mask option window. Make sure the color indicates the selected areas (by default, it picks the masked areas). Opacity at 100%.
7. Invert the Quick Mask (Command I for Mac/Control I for PC).
8. Adjust levels of Quick Mask paying attention to how it affects the shadow.(Command L for Mac/Control L for PC).
9. Exit the Quick Mask by pressing the Q key. You should see a selection (marching ants).
13. Add a white layer underneath that layer (follow the same procedure as #12), so you can see the shadow.
14. Click the layer above and make active. Adjust the shadow using the opacity slider until you feel comfortable with the result.
15. Throw the 2 bottom layers in the trash and merge the 2 top layers (Command E for Mac/Control E for PC).
16. This is the end result - 1 layer with background knocked out (checker board).
It can be saved to any format. Now it can be put on any background while retaining the shadow. If there are any questions or comments, feel free to leave them in the comment section of the blog.