Scattering error in a Vis/IR imaging system is caused by high-order imperfections in the optical surfaces and particulate contaminants of the optical surfaces. When measuring uniform radiometric scenes there is almost zero net effect from scattering, since as much radiance is scattering out of a pixel as is scattering into it. However, when a scene has sharp contrasts this is no longer true, and significant scattering errors result around the edges between bright and dark regions. The VIIRS Calibration Process will include an algorithm to identify pixels with large scattering error. This algorithm estimates scattering by convolving the measured Point Source Transmittance (PST) of the instrument for each band. The PST will be based on, not only the measurement, but also additional degradations expected from post-launch contamination. Remote Sensing measurements of environmental data will be flagged as lower quality due to scattering.