Chrysotype
Encyclopedia
Chrysotype is a photographic process invented by John Herschel
in 1842. Named from the Greek
for "gold", it uses colloidal gold
to record images on paper.
Herschel's system involved coating paper with ferric citrate, exposing it to the sun in contact with an etching
used as mask, then developing the print with a chloroaurate solution. This did not provide continuous-tone photographs.
The modern chemist and photographic historian Dr Mike Ware
has experimented with a reinvention of the process giving more subtle tones.
John Herschel
Sir John Frederick William Herschel, 1st Baronet KH, FRS ,was an English mathematician, astronomer, chemist, and experimental photographer/inventor, who in some years also did valuable botanical work...
in 1842. Named from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
for "gold", it uses colloidal gold
Colloidal gold
Colloidal gold is a suspension of sub-micrometre-sized particles of gold in a fluid — usually water. The liquid is usually either an intense red colour , or a dirty yellowish colour ....
to record images on paper.
Herschel's system involved coating paper with ferric citrate, exposing it to the sun in contact with an etching
Etching
Etching is the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio in the metal...
used as mask, then developing the print with a chloroaurate solution. This did not provide continuous-tone photographs.
The modern chemist and photographic historian Dr Mike Ware
Mike Ware (photographer)
Mike Ware is a chemist and photographer, known for his work in alternative photographic processes, earlier methods of printing photographic images that were succeeded by the more common silver-gelatin used today...
has experimented with a reinvention of the process giving more subtle tones.