2025 Poster Session

Velox Transparent Water Color Stamps, manufactured by Eastman Kodak Co. in Rochester, N.Y., were marketed primarily to professional and amateur photographers and artists for hand-coloring black-and-white photographs. First appearing around 1914, Velox packets contained 12 perforated dye sheets, each separated by paper cover pages that briefly described their intended use. The descriptions were often poetic, with phrases like "A soft, beautiful yellow for use in flower work, sky tints, etc." The 12 colors in a typical Velox packet included Light Yellow, Deep Yellow, Flesh Tint, Brilliant Red, Scarlet, Warm Brown, Foliage Green, Deep Green, Light Blue, Dark Blue, Violet, and Stone Gray. These dyes allowed photographers to hand-tint their images, enhancing aesthetic appeal and offering a more personalized, artistic touch. The practice became popular in an era when color photography was still experimental, and products like Velox provided a simple, accessible solution for adding color to black-and-white prints. This research sought to identify the chemical compositions of the dyes found in an undated Velox Transparent Watercolor Stamps brochure from the Getty Conservation Institute (GCI) photographic study collection. Accurately identifying these dyes can guide conservation efforts, particularly in preserving photographs employing hand-coloring. Several techniques were used to analyze the dyes: Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Surface-Enhanced Raman Spectroscopy (SERS), and Thin Layer Chromatography-SERS (TLC-SERS). Initially, Raman and FTIR spectroscopy provided preliminary spectra for each dye. While many of the dyes exhibited fluorescence under Raman, FTIR analysis yielded some promising results, helping to suggest which aniline dyes were present based on specific spectral peaks. SERS was applied using silver nanoparticles to overcome fluorescence and amplify the weaker Raman signals. This method offered higher sensitivity by quenching fluorescence, allowing vibrational modes to be more clearly detected. Because Raman, FTIR, and SERS are not separation techniques, Thin Layer Chromatography (TLC) was used to isolate individual dye components and determine if any mixtures were present. TLC-SERS proved especially useful when, for example, the two yellow colors were analyzed. While both Light Yellow and Deep Yellow appeared to contain Acid Yellow 23 according to Raman and FTIR, TLC-SERS analysis revealed that Deep Yellow was a mixture of Acid Yellow 23 and Acid Orange 7. The results of this study have potential implications for art historical and conservation research. By identifying the specific dyes used in Velox products, conservators can better understand the materials involved in hand-colored photographs. This research allows for more informed decisions in preserving photographs containing similar aniline dyes.