Chromophotography

The second picture was then superimposed over the first, with a small air gap in between, resulting in a three-dimensional effect.

Messers Porter and Cann were advertising "Chromo-Photographic Portraiture" in the Bury and Norwich Post of 2 August 1854, which clearly relates to painting colour on photographs and by 1856 several photographers were using the term in their adverts, although this use did not catch on.

This pre-dates by 8 years the first reference to the new invention called "chromo-photography" by M. Albert, photographer to the Court in Munich reported in the South London Chronicle of 10 May 1862.

The term "Chromo-photography" was also used to describe a very different photographic technique using chromic acid described in Dr. Hermann Wilhelm Vogel's book The Chemistry of Light and Photography as reviewed in The Examiner of 24 July 1875.

The Bucks Free Press of 2 September 1870 carried an advertisement by the photographer Laz Roberts which said "he is working on entirely new process of his own, Chromophotography, and taking life-like CdVs in Natural Colours", but it is not certain what technique he was using.

Bottom layer of chromophotograph
The bottom layer of an Alexander Seik chromophotograph. The photograph has been printed on salt paper , with heavy colouring. The border is made from cardboard, to maintain an air gap between the two layers.
Top layer of chromophotograph
The top layer of the chromophotograph has been made translucent by treating the paper with wax. Either salt or albumen paper may have been used for this top layer. The colouring on the top layer is not typical for chromophotographs by other photographers. The chromophotograph was originally mounted in a decorative frame, with an oval mask.
Digital reconstruction of chromophotograph
The original chromophotograph has deteriorated, due to yellowing of the paper. This picture is an attempt to reconstruct the original look of chromophotography, using modern Photoshop technology. First, both layers were colour balanced to remove the yellow cast; then the bottom layer was unsharpened to simulate diffusion by the paper; and finally, the upper layer was made 30% translucent.