Waxed paper process

Waxed paper process is an early form of photography. A variation on the calotype process.
Wedge spectrogram is an indication of the spectral sensitivity of a sensitized material by exposing it to a spectrum of light through a graduated gray wedge.

This photographer, using the pen name Rho Delta, wrote as follows in 1863:70 "About six years back, when using the waxed paper process, ...

See also: Plate, Enlarging, Base, Filament, Bromide