Geometry and orientation

Lab activity

OK. Its basic stuff, but there are exact and meaningful orientations of film strips in printers for obvious reasons. But you can get in a muddle thinking about whats right, what ‘looks’ right and what you think should be right.

This video shows a 16mm sequence in the printer gate, seen as by the video camera. It clearly shows an image that we know is the ‘Right’ way up but is flipped Left>Right. The VA optical sound track is to the left AND we should know that this soundtrack actually appears on the right in projection. The sprockets on the printer are on the right so we  know that if this image was copied it would flip L>R  and  Up>Down and would be wrong in projection because to go from any image to projection we turn it 180 degrees.

This sequence shows an upside down image in the gate, with soundtrack also on left. The reason this is slightly annoying for digitisation is because when set up for for film to film copying the bench lens would do the job of correcting the image, turning it 180 degrees. But a video camera (I guess the image is turned 180 degress on the sensor) corrects the viewing image (screen, HDMI output, etc) for our convenience. So this last clip is correct, turning it 180 degrees makes it right.