How were autochromes made?

How were autochromes made?
It was a process that consisted in producing colour photographs on glass plates, as diapositives invented on 17 December 1903 by Louis and August Lumière who improved the technology in the following years and launched the mass production of autochrome plates.
An autochrome plate was covered with three layers: a colourful mosaic of microscopic red, green and blue grains of starch, a coating of lacquer to protect the grains and a layer of a panchromatic photosensitive emulsion intended for black and white photography. During exposure, light penetrated the multi-coloured grains, and the image developed as a positive had natural colours. Exposure of autochrome plates took between 2 and 3 seconds. In Poland, the autochrome technique was used by Henryk Mikolasch and Stanisław Krygowski.

Elaborated by Małgorzata Kanikuła (Museum of Photography in Kraków), © all rights reserved 


See: Photograph Kraków environs, a rural genre scene