Gabriel Lippmann Gist Quotations

The photography of composite colours that exterior objects present posed a harder problem. At first sight it might have been held impossible.

The plate at each point only sends back to the eye the simple colour imprinted. The other colours are destroyed by interference. The eye thus perceives at each point the constituent colour of the image.

This result is due to a phenomenon of interference which occurs within the sensitive layer.

During exposure, interference takes place between the incident rays and those reflected by the mirror, with the formation of interference fringes half a wavelength distant from each other.

The length of exposure (one minute in sunlight) is still too long for the portrait. It was fifteen minutes when I first began my work. Progress may continue.