Spectroscopic analysis of hand-colored photographs and photographic hand-coloring materials
Date
2010-05
Authors
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Publisher
University of Delaware
Abstract
Prior to the advent of color photographic processes, the only method of
producing photographs in color was to apply coloring agents by hand. Though handcolored
photographs from every period of photography can be found in public and
private collections throughout the world, little research has been done in developing
methods for identifying the coloring agents on such photographs. The first aim of this
research was to determine if spectroscopic methods—X-Ray Fluorescence
Spectroscopy, Fourier Transform-Infrared Spectroscopy, Dispersive Raman
Spectroscopy, Scanning Electron Microscopy-Energy Dispersive Spectroscopy, and
Gas Chromatography-Mass Spectrometry—could be used to identify the components
and pigments in period Marshall’s Photo-Oils kits, which were immensely popular
after their introduction in the 1920s and are still produced today. After successfully
identifying the primary components of these paints, the next goal of the research was
to determine which, if any, spectroscopic methods could be used to best identify these
same paints when painted onto a photographic base. Finding that using XRF and
Raman spectroscopy used in conjunction with one another was the best method for this
task, photographs colored with unknown coloring media were examined to see if these
same methods could then be used to identify the colorants. Early results are quite
promising, though further research is needed.