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.
The epidermis is a stratified squamous epithelium, composed of proliferating basal and differentiated suprabasal keratinocytes which acts as the body's major barrier against an inhospitable environment, by preventing pathogens from entering, making the skin a natural barrier to infection.