By Brian Guckian
“I’ve always believed in the magic of movies…and to me, the magic of movies is connected to 35 millimetre…because everyone thinks – you can’t help but think – that when you’re filming something on film, that you’re recording movement. You’re not recording movement – you are just taking a series of still pictures…there is no movement in movies at all – they are still pictures. But when shown at 24 frames a second through a light bulb, it creates the illusion of movement…so that, as opposed to a recording device…when you’re watching a movie – a film print – you are watching an illusion. And to me, that illusion is connected to the magic of movies.” – director Quentin Tarantino, in an interview with Sir David Frost
Motion picture film is currently being replaced in theatrical exhibition with digital video. Yet motion picture film – and motion picture film projection – have many unique characteristics that are difficult to emulate by electronic means.
1. In the Dark
Shutter interruptions in film projection are thought to relax the brain of the viewer; in a typical motion picture projector the shutter occludes the frame about half the time (between c.47% and c.53% of the projection cycle depending on the design of the shutter and the “dwell time” – stationary period – of the projector intermittent movement). The brain has less image “processing” to do, but is also thought to “fill the gaps,” during these dark interludes. The pleasing experience of watching projected film images differs significantly from other image display methods.
2. 3D, Already
Although film is often thought of as a flat strip, it is in fact a three-dimensional solid. Modern processed colour print film typically has up to 13 layers, 9 of them imaging layers; the attractive depth of the film image, often reported by observers, is attributable to viewing through these layers, including the polyester film base, when watching projected film images. If imagined as a solid, a 1:1.85 aspect ratio film image projected onto a 30-foot-wide screen would have a virtual depth of about 2 inches.
3. On Cloud Nine
In colour film, observed film grain is made up of clusters of colour dye clouds ranging in size from about 6 to 15 microns across (0.006 mm to 0.015 mm). These clouds have indistinct edges and are multi-layered, with overlaps between layers. Film grain is a complex three-dimensional pattern arising from the interaction of these clouds, as perceived in the brain of the viewer looking through the projected emulsion layers.
4. The Last Detail
The brain integrates detail in projected film over several cumulative frames rather than from a single frame. The total resolution of motion picture film is significantly greater therefore than the resolution of a single frame. Far from being a hindrance, film grain is felt to aid in the perception of image detail, by way of the phenomenon of stochastic resonance – small amounts of image noise stimulate the human visual system and allow it to perceive more, rather than less, detail. The random distribution of grain both within each frame, and across consecutive frames, contributes greatly to the richness of picture information contained on motion picture film.
5. Transports of Delight
Subtle movement in projected film images reduces the need for the eye to move around while viewing. The human visual system is most responsive when there is movement; if an image is static, the eye will rapidly scan it. If there is slight movement even in a relatively static image, the eye has less work to do and is more relaxed. The “motion” in motion pictures – due to the transport of the film through the projector as well as the constantly-changing grain pattern – greatly benefits the viewing process.
6. Tough Times
Handled and projected properly, today’s print films can be run well over two thousand times without visible degradation – just under a year and a half of continuous running in a typical cinema. Current print stocks feature a tough scratch-resistant backing layer, plus an antistatic layer which reduces dirt attraction.
7. Emotion Pictures
It has been said that Film engages the Heart, whereas Video engages the Intellect. The organic nature of motion picture film, with its randomness and complexity, speaks to the human spirit in a unique way and is extremely difficult to emulate or replace.
Brian Guckian has worked in the fields of film and video projection, picture and sound post-production and film distribution. Based in Dublin, he is a member of the Association of Moving Image Archivists (AMIA) and the British Kinematograph, Sound & Television Society (BKSTS)
Micrograph images of the grain structure of 35-millimetre film courtesy of Kodak. So-called T-grains (triangular and hexagonal shapes) and cubic grains (the cubic ones) are incorporated into film to achieve different absorption of light. T-grain silver halide crystals – squished to become “tabular” (flat) – provide better absorption of some colors in light than conventional silver-halide crystals, without sacrificing desired “grain” in images’ appearance. Eastman Kodak won a 1991 Oscar for that engineering. But silver-halide crystals can be squished only so much. So, in slower film, cubic grains are used that provide an efficient emulsion with fine grain.