Gabriel Lippmann

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.

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 problem of direct colour photography has been facing us since the turn of the last century.

A free life cannot acquire many possessions, because this is not easy to do without servility to mobs or monarchs.

I am a big one for subtlety and empathy. My dad was softly spoken and didn't carry his honours and accomplishments for everyone to see.