The shape of the screen
The ratio of the longest side of a rectangle to the shortest side is called the aspect ratio of that rectangle. The aspect ratio of a ﬁlm or television frame and the relationship of the subject to the edge of frame has a considerable impact on the composition of a shot. Historically, ﬁlm progressed from the Academy aspect ratio of 1.33:1 (a 4:3 rectangle) to a mixture of CinemaScope and widescreen ratios. TV inherited the 4:3 screen size and then, with the advent of digital production and reception, some countries took the opportunity to convert to a TV widescreen ratio of 1.78:1 (16:9). There is a striking similarity between the commercial considerations
involved in the introduction of ﬁlm widescreen in the 1950s and the national politics and commercial debate to establish TV widescreen transmissions in the 1990s. It was hoped to increase cinema attendance by changing the shape of the ﬁlm screen in the mid-twentieth century just as 50 years later it was hoped to sell more television sets by changing its shape. In fact manufacturers were guaranteed to sell more digital widescreen sets if they could convince governments to switch of the existing 4:3 analogue sets and render them obsolete. This chapter discusses how ﬁlm and TV images arrived at their present displayed aspect ratios and the inﬂuences that have changed these shapes over time. As well as the production aspect ratio there is also the aspect ratio of
the screen on which the image is displayed. If there is a mismatch between the aspect ratio of the original and that of the reproduced image, a number of problems arise. Considerations about the diﬀerent shapes of display screens now and in the future and their eﬀect on how the original composition of an image could be protected, are dealt with in Chapters 8 and 9.