Original photographs by Ansel Adams are defined as photographs printed by Ansel Adams from the negatives he made (photographed and developed). Most will range between $4,000 and $70,000.
Keratosis is the term for any condition that is a benign overgrowth  and thickening of the epidermis.
There are three sub-layers within the epidermis itself: the outer stratum corneum, the middle squamous cell layer, and the bottom basal cell layer. The stratum corneum is the visible part of the epidermis and is actually a layer of dead skin cells immediately on the skin's surface. This layer uses a protein called keratin to form a tough barrier between the outside world and the more vulnerable cells inside the skin and body.