Physionotrace

The technique of the physionotrace was invited by G. L. Chrétien in 1784, making it possible to make portraits before the era of photography for relatively low cost and with the option of creating a number of copies. After tracing out through a transparency a silhouette of a person on a piece of paper, this image was decreased in size by means of a complicated mechanism with gears and levers, until it was some 5-7 cm high. Using this small copy of the silhouette on paper, a negative mould of the image was hand-engraved on a copper plate, making it possible to print cards with the portrait on them.