RESUMEN
The total number of black and white slides and photographs requested from staffs of the Faculty of Medicine, Siriraj Hospital were analyzed at the School of Medical Illustration and Audiovisual Technology, between January 2, 1980 to December 28, 1984. Total number of B&W slide was 44,815 slides, of which 11,932 slides (26.62%) were serviced for the Department of Medicine, and 9,012 slides (20.11%) for the Department of Surgery. The tendency of B&W slid services has become lower since 1980 due to a greater requirement of colour slides. The total number of B&W photographs was 50,241 picture, of which 16,153 (32.15%) and 10,412 (20.72%) were serviced for the Department of Medicine and Surgery respectively. It is very interesting to note that the tendency for B&W pictures has not lowered since 1980 as the B&W slides but has increased. This is due to the fact that B&W pictures are still more necessary for printing in medical literature and textbooks than the colour pictures.