A group of professional photo preservationists who operate a website, ScanCafe, list the education requirements for their photo restorers: "Our artists have been through formal training in color concepts, restoration tools, image enhancement techniques, highlight and clipping management, grain reduction and calibration routines. They are proficient and expert in Adobe Photoshop and Corel Draw."
Access a comprehensive clearinghouse of links for photo restoration training on the website "Photo Retouching Restoration." This utilitarian site lists many excellent tutorials on photo retouching, and references informative articles on various photo restorative techniques.
Professional associations like the National Association of Photoshop Professionals, or NAPP, offer video tutorials and forums to educate members in subjects such as, according to the NAPP website: "typography, photo restoration, photo retouching, correction, selection, layers, actions, illustration, web, design."