Tutorials Video

Louis Ducos du Hauron: The Theory Everything Else Implements

By Infinite Creation · Profile

Historical photograph of Louis Ducos du Hauron.

At a Glance

Louis Ducos du Hauron (1837-1920) published the theory of subtractive three-colour photography in 1869: record three separation negatives through red, green and blue filters, then print them in the complementary dyes. Cyan, magenta and yellow, superimposed. Technicolor, Kodachrome, colour negative film and every inkjet printer are implementations of what he described.

Lived: 1837-1920, France
Anchor year: 1869, subtractive three-colour photography
Strand: overlooked, the theory is his, the industries are not

Career

The problem as it stood

Photographic emulsions record brightness, not colour. Reproducing colour requires separating the scene into components, recording each, and recombining them, and in 1869 nobody had established which components, or how to recombine them on paper.

What he actually did

Ducos du Hauron published a complete scheme, and made prints to demonstrate it. Photograph the subject three times through red, green and blue filters. Make a positive from each in the complementary dye, superimpose them. He also anticipated additive screen processes and the anaglyph.

How it worked

Additive mixing adds coloured lights and starts from black. Subtractive mixing removes wavelengths from white light using dyes and starts from white. Paper and film are illuminated by white light, so they must be subtractive: cyan absorbs red, magenta absorbs green, yellow absorbs blue. That distinction is the reason the CMY set is the right one.

What it made possible

All chemical colour photography and cinematography. Technicolor's three-strip process is his scheme mechanised. Kodachrome is his scheme with the dyes formed in a single tripack. Colour negative film and every CMYK printing process follow the same logic.

What happened to him

He worked largely alone, patented widely and profited little, and died in poverty in 1920: more than a decade before Technicolor made his principle commercially enormous.

Where the credit landed

Ducos du Hauron is credited in histories of photography and almost never in histories of film or television, which begin the colour story at Technicolor. Charles Cros published a closely related scheme at essentially the same moment, and the two are usually cited together: Cros appears elsewhere in this corpus for the paleophone. Being sixty years early and dying before the payoff is a recurring shape in this history.

Known For

Additive starts from black and adds light. Subtractive starts from white and removes it.
Film and paper are viewed by reflected or transmitted white light, so they must be subtractive.
Technicolor and Kodachrome are both implementations of an 1869 scheme.

Knowledge Base

What You'll Learn

Colour reproduction is a solved problem from 1869 onward. Everything after is engineering.

Why three

Human colour vision has three cone types, so any colour a person can see can be matched by an appropriate mixture of three suitably chosen primaries. That is a fact about the eye rather than about light: a spectrophotometer would need far more channels. Every colour system in this corpus, from Technicolor to PAL to a phone screen, exploits the same three-channel limitation of human vision.

Where This Fits

Subtractive colour theory underlies colour capture, the first link of the chain traced in A History of Broadcast Technology.

FAQ

Q: What is the difference between additive and subtractive colour?
A: Additive mixing combines coloured lights, starting from darkness, used by screens, with red, green and blue. Subtractive mixing uses dyes to remove wavelengths from white light, starting from white, used by film and print, with cyan, magenta and yellow.

Q: Did Ducos du Hauron make colour photographs?
A: Yes. He produced demonstration prints using his three-negative subtractive method from around 1869, decades before commercial colour photography existed.

Vocabulary

Subtractive three-colour. Producing full colour by superimposing cyan, magenta and yellow images, each removing part of the spectrum from white light. The principle behind colour film and colour printing alike.

Separation negative. A negative recording one part of the spectrum, taken through a coloured filter. A set of them together holds the colour information that a single black and white record cannot.

Superimposition. Layering separate colour records so they combine into one image. Demands precise alignment, since any offset between them shows immediately as coloured edges around detail.

Complementary dye. A dye absorbing one primary colour and passing the others, such as cyan absorbing red. Three of them in combination can reproduce most of the colours the eye distinguishes.

Sources

No document is cited here. Checked 20 August 2026.

The record would be his French patent of 1868 on three-colour photography, together with his book of the following year. French patents of that period are not in the databases reachable from here, and neither the brevet number nor its text could be confirmed, so nothing is linked. The Musée Nicéphore Niépce and the Bibliothèque nationale hold relevant material. This is a gap that a French archive visit closes and a web search does not.