We used a pair of Spanish-made portable 35mm machines. These used 1000w tungsten bulbs; surprisingly, the picture filled the width of the screen for scope and was fairly bright. The built-in changeover system works by simply turning off one bulb while turning on the other; this got "interesting" with prints that had clear leaders immediately before or after the picture. The picture was super-sharp with ISCO Ultra-Star lenses for all formats.
January 2003 photo from the Scott Norwood collection.