A viewing device for a stereo projection system, having a first and a second viewing window, each having an optically filtering filter layer system, wherein each viewing window has a filter spectrum in the visual spectral range having a plurality of pass bands that are separated from each other by blocking regions, and wherein each pass band of the filter spectrum of the first viewing window is covered by an associated blocking region of the filter spectrum of the second viewing window. Each filter layer system can be designed as an absorption filter layer system having a plurality of substances absorbing in differing spectral ranges, wherein at least one of the absorbing substances is a cyanine dye in the supramolecular configuration of a J-aggregate.