Searchlight is an online spectral plotting and filter selection tool provided by Semrock, another prominent manufacturer of optical filters for fluorescence and other optical applications. Similar to Curvomatic, Searchlight allows users to browse and analyze Semrock's extensive range of filter sets. This digital resource features an interactive interface where users can view the transmission and blocking characteristics of excitation, emission, and dichroic filters. It also includes a broad database of fluorophore spectra, which can be overlaid with filter curves to facilitate optimal filter selection for specific fluorescent dyes and experimental setups. Searchlight is invaluable for researchers designing multi-color fluorescence experiments, as it helps in identifying filter combinations that provide high signal-to-noise ratios and minimal spectral bleed-through. The tool's ability to compare and contrast different filter options makes it a critical resource for optimizing fluorescence imaging and detection systems.