Here are a couple of different ways of using a scanned image as a mask: as a Layer Mask or a Clipping Mask.
For over 30 years, Dave Cross has been helping photographers and creative professionals get the most out of their software. Starting with Adobe Illustrator classes in 1987, Dave has taught Photoshop, Illustrator and InDesign to thousands of users around the world. He has a Bachelor of Education, is an Adobe Certified Instructor in Photoshop CC and is a Certified Technical Trainer. Dave has taught at Photoshop World (28 times), spoken at many photography events, written numerous articles and several books, co-hosted Photoshop User TV and has appeared in many DVDs and online courses for Kelby Training and PhotoshopCafe. Dave has been a regular instructor for CreativeLive, and in 2016, 2017 and 2018 was named a MAX Master instructor at Adobe MAX.
Over the last 20 years, Dave has taught Photoshop in every state in the United States, throughout Canada and in Europe, consistently earning rave reviews. Dave is well-known for his engaging style, his humor and his ability to make complex topics easy to understand. In 2009 Dave was inducted into the Photoshop Hall of Fame.
From Dave: Take advantage of my experience of teaching thousands of Photoshop users like you how to be more efficient and creative.