Additive manufacturing (AM) is a rapidly growing field where complex components are produced without complex tooling.  While the desire to move this technology into new defect critical industries exists, it is important to understand that AM processes can, and often do, create flaws within the component.  Therefore, it is important to monitor the process to determine when flaws are formed.  Here we study the vapor plume fluctuations that occur during the deposition of nickel alloy 625 via a custom-built, off-axis multi-spectral sensor during a laser powder bed fusion process. This sensor is designed to simultaneously monitor both excited Cr I Line emissions and Continuum emissions from the vapor plume at very fast rates.  We show that spectral emission lines from the vapor plume relate to processing parameters used during deposition and can be used to enable sensor-based process map development.  We conclude by proposing a novel calibration technique which will permit the correction of intensity variations across the build plate thus enabling analysis on the fly. Expected applications of the work include real-time sensing and control of PBFAM build conditions for increased build quality. Further applications would be the development of rules permitting a qualify-as-you-build approach to save material and time.