Double Single 8

From Super8wiki
Jump to: navigation, search

Double Single 8 by Jörg Polzfuß

Double Single 8 is a small variation of the scaled down gates that only makes sense when the result will only be telecined:
Just put a filter in front of the lens that blocks the light of the upper part of the picture, e.g. hama's "Dual-Image"-filter. Now roll your camera as normal. Once you've reached the end of the film, rotate the filter so that it now blocks the lower part of the picture. Now rewind the film and shoot it again.
The result is a film with two cinemascope-split-frames per frame. It is still projectable by using the same filter in front of the projectors lens. But you won't be able to edit it since the "upper film" most likely would needs other cuts than the "lower film". Nevertheless you can still get the film telecined normally! And using the computer you'll be able to turn this 4:3 video into a 8:3 video with twice the length:
a) Use VirtualDub to split the video into single frames
b) Use a macro in Gimp to copy the upper half of each frame into a new black image -CENTERED in Y-direction- and the lower half into another new black image -CENTERED in Y-direction-.
c) Now use VirtualDub to convert those single frames back into an AVI-file. (The best about this: When you get your film telecined frame by frame, a PAL/Secam-video would have 25 frames per second, a NTSC-video nearly 30 frames per second. In this step, you can tell VirtualDub to restore the real frame-rate of your camera - most likely 18 or 24fps. Hence the resulting AVI-file won't be neither too fast nor too slow!)
d) You can now edit the resulting AVI-file in your normal video editing tool, since it's a normal 4:3 video. But due to the black bars above and below the picture it'll look like a transfered cinemascope-film ;-) (If you've changed the frame-rate in step c: Most video editing tools won't have any problems to work with these frame-rates and will convert these videos to the normal DV/miniDV/DVD/whatever-format without any problems. This "extra conversion" will just take some more calculation time.)

Are there any other drawbacks apart from having the film transfered to video?
Yes: Since you're only using half the frame's height for each video-frame, you'll have to use low-grain-films.

Will this work with every film-format?
Yes, I only decided to name it "Double Single 8" because some of my Single8-cameras can rewind the film without any problems. The only film-format where this won't work is Super8 because the 15m/50ft-super8-cartridges that aren't rewindable by design.
Since some cameras won't be able to rewind the film, you'll have to do this manually in a dark room.

Hint: you'll get better results when masking the filmgate instead of the lens.

Licensing this idea: Since this is a pretty basic and simple idea, you can use it for free and without limitations. The only thing I'll ask for is: Please credit me (German spelling: Jörg Polzfuß, international spelling: Joerg Polzfuss) when using this idea for your own articles or when selling any hardware modified because of this idea.

Licensing problems: It looks like similar approaches have been patented to Mr. Wernick (for a Super8-version in 1974) and to Carena (for a 16mm-version in 1962). Nevertheless these two patents included modifications of the camera's claw, ... .


By Mitch Perkins:
You'd have to mask the gate right up against the film plane, or the mask-line would be soft, which softness would then encroach [black] on the image. Note frame lines are sharp when image is sharp.

Masking right up to the film plane is difficult; a special piece [mask] must be supported on a greater surface than just the inner edges of the gate. Is there room? Also, it must not scratch the film, while being easy to remove for "top & bottom" exposure.

The mod does not provide wider image area (as opposed top widening the gate like in the "SuperDuper 8"-format). Though you would cut your film budget in half, the same *visual* effect is achieved by simply letterboxing a 3:4 image.