For the satisfactory preservation and restoration of photographic glass negatives a sound knowledge of manufacturing techniques is essential. Initial preparation of glass plates, the albumen, wet collodion, dry collodion and gelatine processes are described. A survey of published information on physical, chemical, biological deterioration, recommended storage conditions and enclosures follows. Published recommendations on restoration are presented. These include cleaning of glass plate negatives re-adhesion of emulsion to glass; repair of cracked or broken glass; transfer of emulsion to another base, and duplication. An account is given of the auhtors'original work on process identification, cleaning of gelatine glass plates and restoration of peeling negatives or their transfer to another base. 3 appendices in tabular form: varnishes, formulas, identification processes. Extensive bibliography.