The Masters of Compositing

By: Ned Casey
By: Ned Casey

One of the most common effects both in the analog and digital worlds is compositing. Green screen effects are one example.

One of the most common effects in both the analog and digital worlds is compositing. Green screen effects are one example of compositing effects. Two or more layers are combined to create the illusion of a single image. This is achieved most easily through digital technology however the practice of layering and combining various images has been common in the film world since the 1920s. In the 1930s effects pioneer Linwood Dunn revamped the basic compositing equipment and created a type of optical printer that would be the standard in Hollywood for almost 50 years.


Green screen technology allows for the replacement of background imagery. Linwood Dunn (right) and one of his optical printers.

The optical printer allowed for multiple exposures or “passes” of different film elements that could be timed and then recorded on a new negative. The success of this process in the hands of a master like Dunn has helped create legendary films. Dunn produced all the composite work on King Kong, Son of Kong, the 1939 Hunchback of Notre Dame and assisted Orson Welles and Gregg Toland in the creation of background plates for Citizen Kane. In 1938 he created a sequence in a Howard Hawks film called Bringing up Baby in which Katherine Hepburn is shown dragging a snarling leopard around by a leash. Even today this is an impressive shot. It’s clear the cat is mean and not happy and Hepburn is (literally) yanking his chain pretty hard. It’s downright scary. But it never happened. Dunn composited two “plates” (photographic elements), one with Hepburn, the other with the leopard into a single shot that defies any attempt to find seams. Dunn won numerous awards for his work over the years but perhaps the finest tribute to his genius is the inspiration it provided for directors from the pantheon such as Alfred Hitchcock.


Linwood Dunn worked on the background mattes for the original (and still the best) King Kong (1933). Katherine Hepburn and Cary Grant look like they're in trouble but Dunn's screen magic kept them from being mauled. Dunn used composite matched shots to combine the leopard and the other two stars of Bringing Up Baby.


Hitchcock made great use of special effects over his long and glorious career. He often used practical effects, that is, he utilized real elements in a shot or scene that were developed and carried out in such a way as to heighten the psychological impact or provide a sense of realism. In Suspicion (1941), Cary Grant carries a glass of poisoned milk up a long flight of stairs to help his wife “sleep”. Hitchcock placed a battery powered light bulb in the milk glass which emanated with an eerie glow during Grant’s walk up the dark staircase. 

Cary Grant carries what might be a poisoned glass of milk. Hitchcock placed a lightbulb in the glass to increase the audience's sense of fear for the recipient of this nightcap. Suspicion.

In Foreign Correspondent (1940), he staged a fabulous plane crash into the ocean from the point of view of the cockpit. The viewer is looking from behind the pilot’s seat out through the cabin windows and can see the plane diving toward the ocean. As the plane crashes, ocean water bursts through the breaking glass and inundates the cabin. This effect was created by using a rear screen projection showing the surface of the ocean rushing up to the plane and  huge water tanks were used to create the deluge. Although we are so used to perfectly executed effects, this stunt still looks good precisely because it’s clear that it’s a “hand-made” effect but it works which makes it all the more impressive.

Hitchcock combined real set elements and actors with footage shot from a plane diving towards the ocean. The footage was projected, from behind, onto thin rice paper placed in front of the cockpit window. At the appropriate time, twin tanks of water unleashed hundreds of gallons of water, tearing the paper and flooding the cabin. A neat effect. Foreign Correspondent.

Rear screen projections played a part in almost all of Hitchcock’s films after the early 30s even as late as his last projects Frenzy and Family Plot in the 70s. Screens set up behind the actors (most often used to simulate characters riding in automobiles) showed scenery, street scenes, roadways, etc. which provided a sense of place and action. Hitchcock squeezed this effect for everything he could get out of it. His second directors worked out a system which enabled the scenery to move in response to the actors. If the driver of a car veered to the left, the background moved in the same way at the same “speed”. It’s always fun to watch an old Hitchcock film to see how carefully he applied this effect. He used it to great effect in The Lady Vanishes (1938) most of which takes place on a moving train.


The Lady Vanishes made extensive use of rear projection. Most of the film is set inside a moving train. The projected scenes gave the impression of the world outside the train. Joel McCrea (right) looking veddy English in his bowler hat, crosses a street in Foreign Correspondent. The street scene is a rear screen projection. The man reading the newspaper is Hitchcock.

His use of optical effects became more frequent and more creative throughout the 40s and 50s. In fact the four films of his that were nominated for special effects academy awards all utilized optical effects. One of these, Spellbound (1945), used multiple passes and plates and were combined with artwork and staging designed by the great Surrealist painter Salvador Dali to create a stunning dream sequence. The pseudo-crypto-psychiatric flummery that accompanies the sequence makes it even more fun to watch today but for an audience watching in 1945 this stuff was eye-popping. Many, many lesser directors have tried to copy this sort of fantastical dream sequence but usually not to such a highly polished degree. Not everyone liked it though. Initially this scene, looking into the mind of could-be murderer Gregory Peck, ran over 20 minutes. Producer David Selznick hated it and convinced Hitchcock that theater patrons would be running amok or at least for the exits if he let it go that long.


We’ll look at more of Hitchcock’s effects next time.

You can watch the Spellbound dream sequence here:


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