Lippmann's most famous achievement was the development of a method of color photography based on the interference of light waves. In 1891, he published a paper describing his "integral photography" method, which used a single photographic plate to record both the amplitude and phase of light waves. This allowed him to reproduce colors with great accuracy and detail.
Lippmann's method was based on the principle of interference, which occurs when two or more light waves combine to produce a new wave pattern. The resulting pattern depends on the wavelengths and amplitudes of the original waves. In Lippmann's case, he used a diffraction grating to split a beam of light into its component wavelengths. He then passed this light through a photographic plate coated with a light-sensitive emulsion.
The emulsion recorded the amplitude and phase of the light waves, and this information was used to reconstruct the original image. When the plate was illuminated with white light, the diffraction grating recombined the light waves to produce a full-color image.
Lippmann's method was a major breakthrough in color photography, and it was widely used for many years. Although it has since been replaced by digital methods, Lippmann's work laid the foundation for the development of color photography as we know it today.