The Rotolight spectrascope is an essential device for photographers, cinematographers, lighting technicians and videographers to assess the color spectrum on set or in the field. Viewing the light through the very small spectrascope, a full color spectrum (>CRI 92) looks like a continuous rainbow with no color spikes which appear as vertical lines or missing colors which appear as dark areas or gaps. Using the spectrascope to trouble shoot and identify problem spectrum bands allows you correct the lighting with filters, thus saving yourself hours of tedious post-production work.