VFX Atlas
H 094 / 3211920s

Dunning Process

1927, Carroll Dunning's colour-separation process

Typeface · Diplomata SC

AI illustration: Shipboard actor composited against storm footage.
AI illustration: Shipboard actor composited against storm footage.Illustration generated for the Atlas (AI)View source ↗

Prompt

Apply a Dunning Process treatment as a black-and-white optical composite, separating a clearly lit foreground from the existing setting. Introduce fine silhouette fringes, subtly different contrast between layers, soft background detail, and period film grain. Keep foreground surfaces naturally shaded rather than visibly blue or yellow. Keep the original subject and composition.

Paste it into LetzAI with your own image to apply the effect ↗

Identify

Live actors appear inside a separately filmed setting, with moving silhouettes revealing the background around them. The finished composite is black and white, sometimes with visible edge fringes.

Principle

Yellow-lit actors stand before a blue backing, while a yellow-dyed background positive1 runs against unexposed negative film inside the camera. The positive filters blue light according to its image, while passing yellow foreground light to expose the negative.

Example

Merian C. Cooper and Ernest B. Schoedsack: King Kong, 1933.

Try it out

Look through transparent yellow film at blue and yellow patches on a screen; compare how strongly each patch darkens.

Background

Carroll Dunning introduced this process in the 1920s, and Roy Pomeroy helped develop it for studio use. It combined actors with previously photographed scenery during exposure2, rather than joining two finished images afterward. The camera carried two film strips together, an arrangement called bipack3. A yellow-dyed positive supplied the background image, while a fresh negative recorded the combination. Yellow light illuminated the actors, and blue light came from the backing. Their different transmission through the dyed positive separated foreground from background. Careful lighting was essential, especially around hair, shadows, and reflective costumes.

Distinction

Unlike modern blue-screen compositing, Dunning combined the images photographically inside the camera rather than extracting a digital mask afterward. Its coloured lighting produced a black-and-white result.

Aftermath

It shows how colour separation can control where an image forms, even when the finished picture contains no colour.

Further examples · 5 images

AI illustration: Pilot in cockpit with traveling matte background
02 AI illustration: Pilot in cockpit with traveling matte backgroundAn aviator is shown in a cockpit with a flowing scarf, set against a distant aerial view of a river valley. The difference in grain and light between the pilot and the landscape indicates the use of an in-camera travelling matte process.Illustration generated for the Atlas (AI)
AI illustration: Metropolitan ledge scene using process cinematography
03 AI illustration: Metropolitan ledge scene using process cinematographyTwo men appear to struggle on the edge of a skyscraper overlooking a busy metropolitan street. The seamless yet slightly distinct lighting on the actors compared to the high-angle city background illustrates a classic black and white composite.Illustration generated for the Atlas (AI)
AI illustration: Hiker composited with waterfall background
04 AI illustration: Hiker composited with waterfall backgroundA hiker crosses a wooden bridge in the foreground, with a massive waterfall cascading in the distance. The sharp outline of the figure against the misty, dynamic background points to a sophisticated early optical matting technique.Illustration generated for the Atlas (AI)
AI illustration: Demonstration of the Dunning Process in studio
05 AI illustration: Demonstration of the Dunning Process in studioA side-by-side display shows an actor before a blue screen alongside the final composite of him on a train platform. This setup demonstrates the use of yellow lighting and color-sensitive filtering to isolate the foreground from the background.Illustration generated for the Atlas (AI)

Question

Why did the process need yellow foreground light and a blue backing?

Show possible answer +

The dyed positive transmitted yellow foreground light but selectively absorbed blue light according to the background image. This let one exposure combine both scenes.

Sources