Articles in the Preservation category present 19th and 20th Century efforts to enhance the stability of albumen prints. Writers in the 19th Century recognized the importance of good processing practice, especially focusing on the elimination of fix and the binding of insoluble non-image silver to albumen. Grundy and Haddon in 1863 make a strong case for the preservation benefits of proper washing to remove fix. Both Spiller and Carey Lea provide significant contributions on the sources of highlight yellowing, both focusing their attention on non-image silver bound to albumen. In the 20th Century, Reilly, Severson and McCabe also turn their attention to the effect of residual fix and find a link between elevated relative humidity and the rate of fading and yellowing. The impact of the environment and enclosures, such a mats and boxes, is describd in Reilly's The Albumen & Salted Paper Book from 1980.