Super 8 projectors are multi-bladed for to reduce flicker, but the frequency of the projected images causes banding and strobing effects when recorded with a PAL video camera. A benefit of shooting Super 8 at 18 fps is that the corresponding projection speed renders the picture more smoothly on video. The slightly slowed playback also imparts a somewhat dreamlike feel to the footage without appearing to be conventional slow-motion that is typically filmed at high frame-rates and played back at normal speed. PAL (Phase Alternating Line) is the television system used in the UK – it uses a frame-rate of 25fps.
Film projectors used in cinemas have three-bladed shutters that flash each image three times on the screen to reduce flicker perceived by the audience. Early projectors used a single-bladed 180-degree shutter like those found in film cameras. This design initially found favour as it gave a brighter image than multi-bladed shutters, but it caused flicker as the screen spent half of the time dark, the other half showing the projected image at full brightness, perhaps giving rise to the term for cinema as ‘the flicks’.