Fundamental physical and mechanical properties of albumen photographs are studied. Unsupported albumen with existing cracks can be stretched 1.5% before failure. Hysteresis data show albumen swells and shrinks 14%, between 14-85% RH, and 17%+ when exposed to liquid water. This degree of deformation exceeds albumen's 1.5% capacity to stretch. The paper base modifies the behavior of albumen in photographs. Curl is attributed to mismatch of water and humidity-induced dimensional changes of albumen and paper layers. Photographs continue to shrink when rewet and dried. Albumen has significant rate-of-stain dependent mechanical properties. Slow dimensional changes result in rubber-like behavior. Fast changes, such as those induced by surface swabbing, result in brittle behavior.