To avoid running into unexpected printing costs, it’s a good idea to print separations (called seps around the water cooler) before sending your image to a print shop. That way, you can make sure an extra color hasn’t snuck its way into your document—especially if you’ve toyed with some spot colors that you’re not going to use. However, you probably won’t use Photoshop to print separations—in most cases, you’ll place an RGB or CMYK image in a page-layout program along with text and other images, and then use that program to print the separations.