A Technical Study of Red Paints in the Retouching Layer of Some Wet-Collodion Glass Plate Negatives of Golestan Palace Photo Archive

A technical analysis of red paints used in retouching wet-collodion glass plate negatives from the Golestan Palace photo archive, dating back to the mid-19th century Qajar era, reveals that red lead and red iron pigments were employed with precision. These pigments, identified using micro Fourier transform infrared (µ-FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and stereo microscopy, served distinct purposes: red lead was used to cover boundaries, enhance brightness, and bind masking papers, while red iron corrected emulsion defects and ensured a clear background. The binder in all paints was identified as gum Arabic, a natural resin. This study provides valuable insights into the deliberate use of retouching materials during this period, contributing significantly to the understanding and preservation of historical photographic techniques.

Noohi, S., & Hadian-Dehkordi, M. (2021). A TECHNICAL STUDY OF RED PAINTS IN THE RETOUCHING LAYER OF SOME WET-COLLODION GLASS PLATE NEGATIVES OF GOLESTAN PALACE PHOTO ARCHIVE. 6th International Meeting on Retouching of Cultural Heritage. RECH6. https://doi.org/10.4995/rech6.2021.13624