Unraveling the modified surface of the photographic paper “Japine”
Modification of the surface of a paper intended for coating with a photographic sensitizer will influence both its chemical and physical characteristics. A scientific examination was performed on the photographic paper, Japine, produced by the Platinotype Company from 1906 to 1937 for their platinum, silver, and palladium printing processes. Scanning electron microscopy (SEM) and non-invasive imaging by optical coherence tomography (OCT) reveal the presence of a very thin layer at the paper surface. Detailed investigation by attenuated total internal reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and gas chromatography-mass spectrometry (GCMS) analyses determined that this surface consists of a parchmentized layer created by chemical modification of the paper support rather than the presence of an applied coating. Reverse engineering studies suggest that the paper was prepared by treatment with sulfuric acid under select conditions to modify the structure of the cellulose only at the paper surface. SEM imaging demonstrates that the distribution of the platinum particles that make up the image is significantly altered on surface parchmentized papers compared to unmodified papers.