GUM BICHROMATE HISTORY
– A BRIEF CHRONOLOGY –
In 1798, French chemist, Louis Nicolas Vauquelin discovered chromium during his work on analyses of minerals. He specialized in analysis of minerals as an assistant in chemistry at the Ecole Polytechnique and was a professor at the College de France. He named this new element chrome after the Greek word chromos meaning color. He observed “that chromic acid forms with silver a carmine-red salt which turned purple when exposed to light.” So, he discovered the light sensitivity of one of the chromium compounds, however this chromate was a silver salt so the reaction actually belongs to the photochemistry of silver compounds.
It wasn’t until 1832 that the light sensitivity of bichromate of potassium in the presence of organic (non-silver) salts was discovered. Gustav Suckow has been credited with that discovery.
The first application of printing on paper treated with potassium bichromate was done by Mungo Ponton in 1839 after the publication of the daguerreotype process. Englishman Ponton observed that paper dipped in chromate of potassium, even in the absence of silver salts, was colored brown by the rays of light. His experiments were described by him on May 29, 1839 to the Royal Society of Scottish Artists. The image was ‘fixed’ by mere rinsing in water. Ultimately, he failed to see the light-sensitivity of mixtures of potassium bichromate with gelatin, rubber, etc. These discoveries didn’t come until later. However, Ponton should be recognized as the father of bichromate printing.
In 1840 Edmond Becquerel used starch paste and treated the chromate image with iodine to make it clear and more visible.
In 1843 Hunt tried to find a better printing out method on paper using potassium bichromate and copper sulphate (chromatype process), but it led to no practical results. Nor did his chromacyanotype; paper coated with potassium bichromate and potassium ferricyanide.
Talbot discovered that mixtures of glue and bichromate became insoluble by the action of light. This was patented in England October 29, 1852 for the production of photo etchings on steel by the aid of this chromate mixture. Talbot’s observations on the property of chromated gelatin to swell in water after exposure to light led to a gravure process using glue, potassium bichromate and silver compounds which was patented by Paul Pretsch in England on November 9, 1854 and in France during July 1855.
Frenchman, Alphonse Louis Poitevin studied the reaction of chromates with organic substances in light. He patented the collotype in England during December of 1855. His patent description also stated that colored prints could be obtained if a dye (pigment) is added to (gum arabic) and the unexposed areas are washed away. He exhibited these prints at the Paris “Exposition Universelle” in 1855.
On April 10, 1858 John Pouncy patented pigment prints in England. He used vegetable carbon, gum arabic, and potassium bichromate as the coating but may have substituted bitumen or other pigments for carbon. As stated above, this process was covered by Poitevin’s patent specifications, but Pouncy received part of the prize money anyway which had been offered by the Duke of Luyne (to invent a decent pigment print method) due to the excellent execution of his prints. Therefore, (ethical considerations aside) John Pouncy may be considered the practical founder of printing with gum bichromate.
THOSE WHO CAME AFTER,
AND SOME BOOKS –
Mungo Ponton was born in 1801 at Balgreen in the British Isles. Ponton discovered the action of light on potassium bichromate when coated on paper, which he announced in the same year that Daguerre publicized his photographic process and that Talbot published an account of his discoveries. It was on May 29, 1839 that Ponton disclosed his discovery to the Society of Arts for Scotland, the organization that he was a vice -president of. His discovery was also published in the July, 1839 issue of The Edinburgh New Philosophical Journal. In this, Ponton explained that
“When paper is immersed in the bichromate of potash it is powerfully and rapidly acted on by the sun’s rays. When an object is laid in the usual way on this paper, the portion exposed to the light becomes tawny, passing more or less into a deep orange according to the strength of the light. In this state, of course, the drawing, though very beautiful is evanescent. To fix it, all that is required is careful immersion in water, when it will be found that those portions of the salt which have not been acted on by the light are readily dissolved out; while those which have been exposed to the light are completely fixed on the paper.
At the time that Ponton announced his discovery he was employed as the secretary of the Bank of Scotland. In 1849 he invented a process of photographically recording variations of temperature in a thermometer. He died in Clifton England in 1880 after having been disassociated with photographic activities for many years.
The following is a list of some of the most prominent gum printers of the past; and is intended as a starting point for further study.
FRANCE — Robert Demachy — C. Puyo — Edward Steichen.
AUSTRIA — Heinrich Kuhn — Hans Watzek.
GERMANY — Theodor & Oskar Hofmeister — Rudolph Duhrkoop — Hugo Erfurth.
BELGIUM — Leonard Misonne.
SPAIN — Jose Ortiz Echague.
BRITAIN — Alfred Horsley Hinton — Alexander Keighley -— F. J. Mortimer.
And last but not least, four excellent photo’ history books you might find at Amazon or elsewhere.
**** History of Photography; by Josef Maria Eder; 1945 Columbia University Press, New York.
** A Concise History of Photography; by Helmut Gernsheim in collaboration with Allison Gernsheim; 1965 Grosset and Dunlap, New York.
*** The history of Photography: It’s relation to Civilization and Practice; by Dr. Erich Stenger; 1939 Mack Printing Company. Easton, Pennsylvania.
**** Photography’s Great Inventors; by Louis Walton Sipley; 1965 American Museum of Photography. Philadelphia. This book supplied the preceding biography on Ponton and included a portrait of him. A four-star book for sure.