Ponton, Mungo (DNB00)
PONTON, MUNGO (1802–1880), photographic inventor, only son of John Ponton, farmer, was born at Balgreen, near Edinburgh, on 23 Nov. 1802. He was admitted writer to the signet on 8 Dec. 1825, and was a founder and subsequently secretary of the National Bank of Scotland.
Ill-health caused him to relinquish his professional career, and he devoted his attention to science. On 29 May 1839 he communicated to the Society of Arts for Scotland ‘a cheap and simple method of preparing paper for photographic drawing in which the use of any salt of silver is dispensed with’ (Edin. New Phil. Journal, xxvii. 169). In this paper he announced the important discovery that the action of sunlight renders bichromate of potassium insoluble, a discovery which has had more to do with the production of permanent photographs than any other. It forms the basis of nearly all the photo-mechanical processes now in use. The developments of Ponton's method are stated in ‘Reports of the Juries of the Exhibition of 1862,’ class 14, p. 5. In 1849 he communicated to the ‘Edinburgh New Philosophical Journal,’ xxxix. 270, an account of a method of registering the hourly variations of the thermometer by means of photography. A list of his papers, which mainly relate to optical subjects, is in the ‘Royal Society Catalogue of Scientific Papers.’ He became fellow of the Royal Society of Edinburgh in 1834. He died at Clifton on 3 Aug. 1880.[Authorities cited, and Photographic News, 20 Aug. 1880, pp. 402–3; Proceedings of the Royal Society of Edinburgh, xi. 100; List of Members of the Society of Writers to the Signet, p. 168.]