Finlay, Thames, Dufay, and Paget color screen process collections: Using digital registration of viewing screens to reveal original color

TL;DR

This paper presents a digital method to reconstruct original colors of early additive color screen photographs from negatives and transparencies, using infrared imaging and open-source software, to preserve cultural heritage.

Contribution

The authors introduce a novel open-source software tool for digitally recreating original color filter patterns in early color photographs, enabling restoration of faded or monochromatic images.

Findings

Successful digital reconstruction of original colors from negatives

Infrared imaging eliminates the need for physical color filters

Restoration of early color photographs enhances cultural heritage preservation

Abstract

We discuss digitization, subsequent digital analysis and processing of negatives (and diapositives) made by Finlay, Thames, Dufay, Paget, and similar additive color screen processes. These early color processes (introduced in the 1890s and popular until the 1950s) used a special color screen filter and a monochromatic negative. Due to poor stability of dyes used to produce color screens many of the photographs appear faded; others exist only in the form of (monochromatic) negatives. We discuss the possibility of digitally reconstructing the original color from scans of original negatives or by virtue of infrared imaging of original transparencies (which eliminates the physically coupled color filters) and digitally recreating the original color filter pattern using a new open-source software tool. Photographs taken using additive color screen processes are some of the very earliest color images of our shared cultural heritage. They depict people, places, and events for which there are no other surviving color images. We hope that our new software tool can bring these images back to life.