an image projector has a pulsed or similar light source of high intensity and high heat emission housed in an opaque box having a light - diffusing glass panel in its forward side which is spaced behind a vacuum film - holding plate having a glass center . between the box light and the film - holding plate is a compartment which is open on the front and back and is sandwiched between the light diffusing glass panel of the box light and the film - holding plate such that no light escapes into the room . said compartment thus comprises an isolation chamber which passes light to the film but not heat . the box light and the isolation chamber each has its own blower system and independent , specially baffled vents such that air between the two does not intermix . the vents are so designed as to permit discharge of the air but inhibit the egress of light therethrough .