Rotolight (RL-SCOPE) Spectrascope lighting spectrum analysis tool including leather pouch and keyring. Complete with a leather pouch and keyring, the Rotolight Spectrascope will allow you to analyse any visible light source for either dark areas or colour banding. This will tell you if the light source is deficient or peaking at particular wavelengths. You can then compensate by adding opposite filters on the colour wheel (eg magents to counter an excess in green), top give a more even, continuous spectrum.