Definite Identifiers of Silver Dye Bleach Prints

Among diverse contemporary colour prints, silver dye ­­bleach prints and chromogenic prints are difficult to differentiate. They share similar visual characteristics and can use identical supports and surface finishes. However, their image-forming dyes differ, resulting in disparate conservation and restoration needs. This study aimed to determine practical measures for unambiguously differentiating between these two print types. Identifying characteristics—referred to here as ‘identifiers’—were collected from popular conservation sources and a mixed-method questionnaire survey. The accuracy and feasibility of these identifiers were evaluated against known prints sets. The examination made use of water droplets, various light sources, digital 3D microscopy, and spectrophotometry. The results dichotomised these identifiers into ‘definite’ or ‘indefinite’ with ‘definite identifiers’ being able to discriminate independently. Only five out of 23 entries were termed definite identifiers. Azo dyes—image dyes of silver dye bleach prints—were established as the only constant properties of this print type. These findings were integrated into a flowchart to guide differentiation with the main recommendation being to deviate from indefinite identifiers to save time and effort. Parts of this work have been submitted in partial fulfilment of the requirements for a Master of Science degree at the University of Amsterdam in 2020.