Insights into the stratigraphy of gelatin-based emulsion in historical dry plate photographic negatives: A multi-analytical approach
Year: 2025
Authors: Balbas D.Q., Maestro-Guijarro L., Carmona-Quiroga P.M., Oujja M., Castillejo M., Cattaneo B., Bernardoni A., Barbone AS., Cagnini A., Striova J.
Autors Affiliation: CNR, Natl Inst Opt CNR INO, Largo E Fermi 6, I-50125 Florence, Italy; CSIC, Inst Quim Fis Blas Cabrera IQF, C Serrano 119, Madrid 28006, Spain; Opificio Pietre Dure MiC, Lab Restauro Cartacei & Membranacei, Viale F Strozzi 1, I-50129 Florence, Italy; Museo Galileo, Piazza dei Giudici 1, I-50122 Florence, Italy; Opificio Pietre Dure MiC, Sci Lab, Viale F Strozzi 1, I-50129 Florence, Italy.
Abstract: This research investigates historical gelatin dry plate negatives’ chemical composition and stratigraphic structure through a comprehensive multi-analytical approach. Our methodology integrated optical and laser-based techniques, with microscopies, including Optical and Scanning Electron Microscopy – Backscattered Electrons (SEMBSE) and Non-linear Optical Microscopy (NLOM) in its Multi-photon Excitation Fluorescence (MPEF) modality to analyze stratigraphy. MPEF enabled us to overcome the limitations associated with light absorption encountered in other optical techniques. Chemical analysis using Laser-Induced Breakdown Spectroscopy (LIBS), Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (SEM-EDS), and micro-Raman spectroscopy allowed for the classification of negative types based on specific compositional materials, such as synthetic dyes. Our findings contribute to the knowledge of dry plate negative composition and stratigraphy, the aspects that have seldom been investigated. The information retrieved is crucial for understanding the realization and degradation mechanisms of these valuable artifacts, often prone to delamination and flaking, and can inform conservators to better treat historical dry plate photographic negatives.
Journal/Review: MICROCHEMICAL JOURNAL
Volume: 212 Pages from: 113379-1 to: 113379-10
More Information: This work was supported by EU Horizon 2020 (GA n.871034), Tuscany Region (Grant No. CUP B53D21008070008), Museo Galileo, El.En. group, and the National Institute of Optics from the National Council of Research (CNR-INO), European Union NextGenerat ionEU – National Recovery and Resilience Plan (NRRP) (Project code IR0000029-CUP-B63C22000730005), Spanish State Research Agency (PID2022- 137017OB-I00/AEI/1013039/501100011033), Regional Government of Madrid (TEC-2024/TEC-39).KeyWords: LIBS; LIF; mu-Raman; Non-linear optical microscopy; Photographic negatives; SEM-EDS; StratigraphyDOI: 10.1016/j.microc.2025.113379
