Film Laboratory Manuals as Sources for the Reconstruction of Colour in Silent Film Restoration.

Abstract

Documentation is a fundamental phase of the film restoration process, essential for collecting information that supports decisions taken throughout the workflow. Sources may vary depending on the specific restoration project and can include film elements or film related materials such as photographs, posters, press clippings, ephemera, music scores, screenplays, censorship or copyright documents, technical documentations, and archival or bibliographical references. Among these, film laboratory manuals represent one of the sources especially for technical information. In particular, this contribution focuses on the use of lab manuals as a reference for colour restoration of silent films.

Chemical formulas contained in lab manuals can provide critical information for the conservation, reconstruction, and restoration of historical colour processes. As with other sources, lab manuals must be cross-referenced with the other documentation collected for the project to ensure their reliability. A particularly effective approach involves comparing colour formulas with the results of scientific analyses conducted on film materials.

Understanding the nature of colour through scientific analysis is useful from both conservation and restoration perspective: identifying the composition and degradation of colourants contributes to write a better long-term conservation plan and allows a more accurate characterisation and reconstruction of original film colourization. Moreover, compare analytical data with historical formulas provides information for building a database to support future colour restoration.

As a case study, this contribution presents the recent collaborative research by the Cineteca Nazionale and the Chemistry Department of the University of Milan, introduced at the XIX Colour Conference 2024. The project applied spectroscopic analyses to the most common silent-era colourisation techniques (pochoir, tinting, and toning) and compared the results with corresponding formulas published in lab manuals of the time.