Aproximaciones teóricas para la estudio de las transfor- transfor-maciones demográficas

At the same moment that we perceive the identity of an object within a frame, we are also aware of the spatial relationship between the object and the frame. These frame ‘field of forces’ exert pressure on the objects contained within the frame and all adjustment to the composition of a group of visual elements will be arranged with reference to these pres-sures. Different placement of the subject within the frame’s ‘field of forces’ can therefore induce a perceptual feeling of equilibrium, of motion or of ambiguity (see figure opposite).

The closed frame compositional technique is structured to keep the attention only on the information that is contained in the shot. The open frame convention allows action to move in and out of the frame and does not disguise the fact that the shot is only a partial viewpoint of a much larger environment.

Frames within frames

The ratio of the longest side of a rectangle to the shortest side is called the aspect ratio of the image. The aspect ratio of the frame and the rela-tionship 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 Cinema-scope and widescreen ratios. TV inherited the 4:3 screen size and then, with the advent of digital production and reception, took the opportunity to convert to a TV widescreen ratio of 1.78:1 (a 16× 9 rectangle).

Film and television programmes usually stay with one aspect ratio for the whole production but often break up the repetition of the same projected shape by creating compositions that involve frames within frames. The simplest device is to frame a shot through a doorway or arch which emphasizes the enclosed view, or by using foreground masking an irregular ‘new’ frame can be created which gives variety to the constant repetition of the screen shape. The familiar over-the-shoulder two shot is in effect a frame within a frame image as the back of the foreground head is redundant information and is there to allow greater attention on the speaker and the curve of the head into the shoulder gives a more visually attractive shape to the side of the frame.

There are compositional advantages and disadvantages in using either aspect ratio. Widescreen is good at showing relationships between people and location. Sports coverage benefits from the extra width in following live events. Composing closer shots of faces is usually easier in the 4:3 aspect ratio, but as in film during the transition to widescreen framing during the 1950s, new framing conventions are being developed and old 4:3 compositional conventions that do not work are abandoned.

The shared priority in working in any aspect ratio is knowing under what conditions the audience will view the image.

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A field of forces can be plotted, which plots the position of rest or balance (centre and midpoint on the diagonal between corner and centre) and positions of ambi-guity (?) where the observer cannot predict the potential motion of the object and therefore an element of perceptual unease is created. Whether the object is passively attracted by centre or edge or whether the object actively moved on its own volition depends on content.

The awareness of motion of a static visual element with relation to the frame is an intrinsic part of perception. It is not an intellectual judgement tacked on to the content of an image based on previous experience, but an integral part of perception.

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Widescreen

The world-wide change-over period from mass viewing on a 4:3 analogue set to mass viewing on a 16:9 digital monitor, and therefore mass programme production for 16:9 television, will take many years. The tran-sition period will require a compromise compotran-sition (see opposite) and many broadcasters are adopting an interim format of 14:9 to smooth the transition from 4:3 to full 16:9. But the compositional problems do not end there. The back-library of 4:3 programmes and films is enormous and valuable and will be continued to be transmitted across a wide range of channels in the future. The complete image can be viewed on a 16:9 screen if black bars are displayed either side of the frame (see (a) oppo-site). They can be viewed by filling the full width of the 16:9 display at the cost of cutting part of the top and bottom of the frame (see (c) oppo-site) or, at the viewer’s discretion, they can be viewed by a non-linear expansion of picture width, progressively distorting the edges of the frame to fill the screen (see (b) opposite).

Viewfinder set-up

As many broadcast organizations have adopted the 14:9 aspect ratio as an interim standard, cameramen shooting in 16:9 follow a ‘shoot and protect’ framing policy. The viewfinder is set to display the full 16:9 picture with a graticule superimposed showing the border of a 14:9 frame and a 4:3 frame. Significant subject matter is kept within the 14:9 border or, if there is a likelihood of the production being transmitted in 4:3, within the smaller 4:3 frame. The area between 16:9 and 14:9 must be still usable for future full digital transmissions and therefore must be kept clear of unwanted subject matter. Feature film productions that were shot in 4:3 but were intended to be projected in the cinema with a hard matte in widescreen can sometimes be seen in a TV transmission with booms, etc., in the top of the frame that would not have been seen in the cinema. ‘Shoot and protect’ attempts to avoid the hazards of multi-aspect viewing by centring most of the essential information. This does of course negate the claimed advantages of the widescreen shape because for the transitional period the full widescreen potential cannot be used. For editing purposes, it is useful to identify within the colour bars the aspect ratio in use. Some cameramen in the early days of widescreen video shooting would frame up a circular object such as a wheel or lens cap to establish in post-production if the correct aspect ratio was selected.

The same size camera viewfinders used for 4:3 aspect ratio are often switched to a 16:9 display. This in effect gives a smaller picture area if the 14:9 ‘shoot and protect’ centre of frame framing is used and makes focus and following distant action more difficult. Also, video cameramen are probably the only monochrome viewers still watching colour TV pictures. Colour is not only essential to pick up individuals in sports events such as football where opposing team shirts may look identical in monochrome, but in all forms of programme production, colour plays a dominant role in composition.

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Composition problems will continue while 16:9 and 4:3 simultaneous productions are being shot during the analogue/digital changeover. They neither take full advantage of the width of 16:9 nor do they fit comfortably with the old 4:3 shape.

After many years of dual format compromise composition, the resultant produc-tions will continue to be transmitted even though 16:9 widescreen will be the universal format. The only safe solution is the ‘protect and save’ advice of putting essential information in the centre of frame but that is a sad limitation on the compositional potential of the widescreen shape.

Viewing 4:3 pictures on a 16:9 display

4:3 aspect ratio picture displayed on 16:9 set with black borders.

Complete 4:3 aspect ratio picture displayed on 16:9 set with progressive rate of expansion towards the vertical edges of the screen. With this system people change shape as they walk across the frame.

4:3 aspect ratio picture displayed on 16:9 set. The 4:3 aspect ratio picture has been

‘zoomed’ in to fill the frame cropping the 16:9 picture edge

14:9 picture edge Picture safe 5%

Graphics safe 10%

4:3 frame is approximately the same as the vertical borders of the 5%

picture safe area. 4:3 safe area is not indicated otherwise there would be more cursors than viewfinder picture

(a)

(b)