SILVER-MIRRORING EDGE PATTERNS: DIFFUSION-REACTION MODELS FOR THE FORMATION OF SILVER MIRRORING ON SILVER GELATIN GLASS PLATES
GIOVANNA DI PIETRO, & FRANK LIGTERINK
ABSTRACT—The silver mirroring that can be seen on many historical silver gelatin photographic glass plates is typically observed to be distributed in certain specific and distinct patterns. A study of these patterns gives information on the causes of silver mirroring and on the detailed nature of the degradation mechanism. This article presents two mathematical models based on the diffusion and reaction of gases that explain the formation of silver-mirroring edge patterns in the case of plates kept in stacks and in the case of plates freely exposed to environmental gases. The predictions are compared with the patterns found on historical plates and with the patterns artificially produced on new plates.
2. PRESENT KNOWLEDGE OF SILVER MIRRORING
4. EXPERIMENTAL PART
a: Appendix , Materials , References , Author Information