AN EXPERIMENT DESIGNED TO DISCOVER WHETHER THERE WERE DIFFERENCES IN LEARNING WHICH COULD BE ATTRIBUTED TO DIFFERENCES IN ROOM ILLUMINATION, VIEWING ANGLE, AND DISTANCE FROM THE SCREEN AS THEY RELATED TO THE CABINET-TYPE PROJECTOR WAS PRESENTED. PARTICIPANTS WERE 721 TRAINEES AT THE GREAT LAKES NAVAL TRAINING STATION. THE TASK CHOSEN WAS THE ASSEMBLY OF THE BREECH BLOCK OF AN ANTIAIRCRAFT GUN. ALTHOUGH MOST NAVY TRAINEES COULD NOT PERFORM THE TASK WITHOUT INSTRUCTION, THEY LEARNED THE ASSEMBLY IN A FEW MINUTES WITH AN APPROPRIATE FILM. HALF OF THE TRAINEES SAW THE SAME FILM UNDER DARKENED ROOM CONDITIONS. A TEST ROOM WAS SET UP WITH 50 SEATING POSITIONS AT VARYING ANGLES OF VIEW AND AT VARYING DISTANCES FROM THE SCREEN. FOLLOWING A FILM SHOWING, THE TRAINEES WERE TESTED ON THEIR ABILITY TO ASSEMBLE BREECH BLOCKS. THE EVIDENCE INDICATED THAT PERFORMANCE WAS BETTER UNDER CONDITIONS OF DAYLIGHT IN THE OPTIMUM VIEWING AREA. OPTIMUM VIEWING CONDITIONS WERE WITHIN 30 DEGREES OF THE CENTER LINE. OPTIMUM VIEWING POSITIONS WERE WITHIN 12 SCREEN WIDTHS OF THE SCREEN. THE FOREGOING FACTORS SHOULD BE TAKEN INTO CONSIDERATION IN TRAINING SITUATIONS WHEN TRAINEES PRACTICE A SKILL DURING A A FILM SHOWING.