DEVCOM Army Research Laboratory (ARL) 1 article published in JoVE Chemistry ARL Spectral Fitting as an Application to Augment Spectral Data via Franck-Condon Lineshape Analysis and Color Analysis William R. Roberts1,2, Thomas N. Rohrabaugh1, Ryan M. O'Donnell1 1DEVCOM Army Research Laboratory (ARL), 2Department of Chemistry, State University of New York at Buffalo This protocol introduces Franck-Condon Lineshape Analyses (FCLSA) of emission spectra and serves as a tutorial for the use of ARL Spectral Fitting software. The open-source software provides an easy and intuitive way to perform advanced analysis of emission spectra including excited state energy calculations, CIE color coordinate determination, and FCLSA.