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Rear Screen Projection

Published : 1st October 2004


Has anyone done any rear screen projection with slides recently?

I have done rear projection with 35mm projectors but this upcoming shoot requires a still photograph projected as a fairly realistic background. basically...a poor man's translite!

I am curious to know what kind of projectors are out there that can provide an image of about 12'x20' with enough illumination for 500ASA at about a T2.8.

My other concern is the stage we are in is only 70' long so I am hoping the projector will have different lenses or a wide zoom to account for a short distance to the rear screen

Thanks in advance.

Dylan Macleod, csc
www.dylanmacleod.com
Toronto, Canada



Dylan Macleod, csc wrote:

>...I have done rear projection with 35mm projectors but this upcoming >shoot requires a still photograph projected as a fairly realistic >background. basically...a poor man's translite!

I think I'm safe in saying it ain't gonna happen. First, I don't believe you can get enough screen intensity (about 40 footlamberts on the front of the screen) on any screen that is diffuse enough to permit a "fairly realistic" projection from less than 70' away. And you'll need an arc slide projector, which are not common. If the screen is somewhat translucent, which virtually all rear screens are, you are going to get a hot spot on the lens axis and dark corners unless you use a longer than normal lens and a l-o-n-g throw.

The last time we did rear screen for a shot inside an auto, we projected 35mm mp film with a xenon arc projector from almost 70 feet onto a screen that was only about 7 feet wide. We got T2.8 for EI 320 film.

Now if this were a front projection it would be fairly easy. We've done front projection from 35mm slides using only a Carousel 500w projector filling a 16' screen, shooting EI 25 film at T2.8.

Better go green screen or a real translite.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614



>I am curious to know what kind of projectors are out there that can >provide an image of about 12'x20' with enough illumination for 500ASA >at about a T2.8.

I don't think there are any standard slide projectors that can match the intensity of a 35 film projector. Years ago a friend of mine decided to give up the role of starving filmmaker and rep a French company that made a projector that projected 8x10 transparencies. It used a HMI lamp housing. He travelled around the US projecting images onto tall buildings and other large surfaces.

You might consider blue/green screen for a better quality image.

There's also the method of projecting your image via a partially silvered mirror 45 degrees in front of the camera lens onto that 3M product, Scotchlite. The image falls on the foreground subject as well but doesn't seem to read when compared to the intensity of the Scotchlite. I don't know if this material is available or workable for a 12x20 screen.

Edwin Myers, Atlanta dp



Edwin Myers wrote :

>...There's also the method of projecting your image via a partially >silvered mirror 45 degrees in front of the camera lens onto that 3M >product, Scotchlite.

That's called front projection, the method I described. The Scotchlite material was #7610 for higher gain, #7615 for higher contrast. I don't know whether or not they are still producing it. EPS (Environmental Projection Systems) in San Marcos, Texas used to be a company that sold screens made from these materials, as well as the projectors for studio portraiture. We bought a 16x20 screen from them, but it has been almost 20 years, so I have no idea whether or not they are still in business. Portraiture with front projection seems to have waned.

I believe Mark Weingartner can give you a lead on someone still promoting front projection systems for film.

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614



Wade Ramsey wrote :

>I believe Mark Weingartner can give you a lead on someone still >promoting front projection systems for film.

New(ish) product, new application, same old technology :

http://www.reflecmedia.com/Chromatte/Chromatte.htm

Tom Townend,
Cinematographer/London.



Some links to front screen projection with the Scotchlite material :

http://www.digitalgreenscreen.com/smptetess.html

http://graphics.stanford.edu/courses/cs99d-00/projects/BrookeHanson-specialfx.ppt

John Pytlak
Eastman Kodak Company



Hi,

>Scotchlite...front projections...no idea whether or not they are still in >business.

Wonder if this would work with one of those green-screen reflectors from Reflecmedia, the type used with an LED ringlight.

It'd need to be in really good nick.

Phil Rhodes
Video camera/edit
London