{"id":3081,"date":"2026-10-30T10:00:00","date_gmt":"2026-10-30T17:00:00","guid":{"rendered":"https:\/\/cinemagear.com\/blog\/?p=3081"},"modified":"2026-10-29T16:18:32","modified_gmt":"2026-10-29T23:18:32","slug":"cinema-engineering-rear-process-projector-2","status":"publish","type":"post","link":"https:\/\/cinemagear.com\/blog\/2026\/10\/30\/cinema-engineering-rear-process-projector-2\/","title":{"rendered":"Cinema Engineering Rear Process Projector"},"content":{"rendered":"\n

Back in the 80’s I was working on several shows that needed to combine matte paintings with live action photography. One of the matte painting processes we used at the time involved a camera on a pedestal that was aimed at an easel that held a rear projection screen and a matte painting on a sheet of glass. The matte painting had an open area in the glass that the live action image could be photographed through. Behind the easel was the projector that was used to project the live action plates onto the rear process screen so the camera could photograph the matte painting and the live action plate at the same time, making a composite image. <\/p>\n\n\n\n

\"Cinema<\/figure>\n\n\n\n

The primitive equipment we had in the studio at the time left us with a very limited workflow. To make a composite shot of the matte painting and live action, you would load your live action plate in the projector, focus the image on the RP screen, take the single button control for the projector back to the camera, focus and setup the camera for the composite shot, then alternately advance the projector one frame and then shoot a frame with the camera, both with separate remotes. These remotes only advanced the camera and the projector each one frame at a time. <\/p>\n\n\n\n

\"Cinema<\/figure>\n\n\n\n

This seemed tedious to me, so I set about designing a rear process system where all of the projector functions and camera functions could be better synchronized. This is one example of the four projectors I built that incorporated the ability to remotely run the projector forward or reverse, focus the lens, and shoot one frame of film, all from a single hand controller that could be used from the camera’s position. <\/p>\n\n\n\n

\"Cinema<\/figure>\n\n\n\n

That meant that once the projector was set up, the camera operator wouldn’t have to go back and forth to deal with the projector until the shot was complete (unless there was a problem). I built these projectors around some existing parts, starting with the bullet head lamp house from an optical printer, and a stock Acme optical printer projector.\u00a0<\/p>\n\n\n\n

\"Cinema<\/figure>\n\n\n\n

Using these components, I constructed a framework to hold them in the correct orientation, and that would allow me to incorporate a servo motor controller to focus the lens, a stepper motor to run the projector, the electronics to support the hand controller, a built-in variac to vary the voltage to the lamp, a voltage meter to properly set voltage to the lamp, an hour totalizer to keep track of how many hours the lamp had been used, a compressed air system to keep the film and lamp house cool, a water cell to remove some of the infrared from the light path, and a slide-in filter box that could be used with wratten filters for color correction. <\/p>\n\n\n\n

\"Cinema<\/figure>\n\n\n\n

The lamp house could be adjusted with six axes of adjustment in order to get the light bundle in exactly the right place so the RP image was flat, even, and with no hot spots. This particular projector was built for Mark Sullivan and was used on many of his projects. I have temporary custody of the projector in a state of disrepair after it has travelled through numerous owners, and it is now destined to be broken up for parts and sent on to new homes.<\/p>\n\n\n\n

\"Cinema<\/figure>\n","protected":false},"excerpt":{"rendered":"

Back in the 80’s I was working on several shows that needed to combine matte paintings with live action photography. One of the matte painting processes we used at the time involved a camera on a pedestal that was aimed at an easel that held a rear projection screen and a matte painting on a […]<\/p>\n","protected":false},"author":1,"featured_media":3074,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[5,4],"tags":[33,123],"class_list":["post-3081","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-accessories","category-cameras","tag-35mm","tag-rear-process-projector"],"_links":{"self":[{"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/posts\/3081","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/comments?post=3081"}],"version-history":[{"count":1,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/posts\/3081\/revisions"}],"predecessor-version":[{"id":3082,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/posts\/3081\/revisions\/3082"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/media\/3074"}],"wp:attachment":[{"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/media?parent=3081"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/categories?post=3081"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cinemagear.com\/blog\/wp-json\/wp\/v2\/tags?post=3081"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}