<P> The first decline in the theatrical 3D craze started in August and September 1953 . The factors causing this decline were: </P> <Ul> <Li> Two prints had to be projected simultaneously . </Li> <Li> The prints had to remain exactly alike after repair, or synchronization would be lost . </Li> <Li> It sometimes required two projectionists to keep sync working properly . </Li> <Li> When either prints or shutters became out of sync, even for a single frame, the picture became virtually unwatchable and accounted for headaches and eyestrain . </Li> <Li> The necessary silver projection screen was very directional and caused sideline seating to be unusable with both 3D and regular films, due to the angular darkening of these screens . Later films that opened in wider - seated venues often premiered flat for that reason (such as Kiss Me Kate at the Radio City Music Hall). </Li> <Li> The few cartoons made in 3D had a "cardboard cutout" effect, where flat objects appeared on different planes . </Li> <Li> A mandatory intermission was needed to properly prepare the theater's projectors for the showing of the second half of the film . </Li> </Ul> <Li> Two prints had to be projected simultaneously . </Li> <Li> The prints had to remain exactly alike after repair, or synchronization would be lost . </Li>

Who invented 3d graphics technology used in films