  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.
