AIC's 53rd Annual Meeting

Colorant Detectives: An Interactive Dichotomous Key for Multiband Imaging

L. M. Ramsey, The Metropolitan Museum of Art

The Colorant Field Guide is an online, interactive tool designed to aid in the visual interpretation of colorants on paper based on their responses to visible (VIS 380-650nm), ultraviolet induced fluorescence (UVF 420-650nm), ultraviolet reflected (UVR 320-400nm), and reflected infrared radiation (IR 780-1100nm [850 peak]). By employing standardized vocabularies and metrics like CIELAB and Munsell color systems, the guide ensures rigorous, reproducible, and communicable results.

Rather than relying on static research papers, black-box algorithms or automated false color post-processing systems to locate and provide results, users must navigate through a decision tree that exposes them to the various factors that influence sample behavior, including light absorption, fluorescence, and reflectance. This process demystifies colorant response by breaking it down into manageable steps, helping users to build a strong foundation of knowledge that can be applied in real-world conservation scenarios.

Transparency in documenting light/radiation sources, filters, and post-processing techniques is emphasized to achieve consistency and comparability across institutions. This approach fosters collaboration and enhances the collective knowledge base in conservation while addressing the inherent uncertainties in multispectral imaging and dichotomous identification methods.

Building a dynamic dichotomous key involves both a logical framework and technical implementation to ensure usability and functionality. I designed it to be simple and effective using basic HTML, CSS and JavaScript languages to make the key interactive, process user input, and display results dynamically. To translate the flow chart to an interactive framework, it was important to list each colorant and their responses in a standardized order. This order helps build a logical, hierarchical flow. At each decision point, users are guided either to the next question or to a result, allowing for the possibility of future expansion.

In addition to the key, I am developing a pictorial atlas of colorants recorded under these imaging techniques to serve as a visual reference. This project is intended to be publicly accessible and expandable, allowing users to submit data that meets established criteria. These submissions will be clearly credited, promoting transparency and collaboration. By encouraging contributions, this tool fosters a cooperative research environment, enriching the field of cultural heritage preservation and providing a shared resource for the broader academic community.

Dichotomous keys have long been valued in education, particularly for teaching critical thinking, systematic problem-solving, and observation skills. As multiband imaging becomes a standard practice in more institutions, this accessible tool will help ensure visual literacy in the conservation field remains strong.