In 1854, Paul Pretsch (1808-1873) patented photogalvanography and together with Roger Fenton (1819-1869) went on to establish the Photogalvanographic Company in 1856 to commercialize his new process. Duncan C. Dallas was hired as the company manager. To their surprise, Dallas was granted provisional protection for his own patent in June of 1856 on Improvements in chemical preparations applicable to the photographic and photogalvanographic processes. Pretsch and Fenton asked him to leave the company and many years of litigation followed.
In the September 11, 1863 issue of The Photographic News, Dallas published the abstract “Photo-Electric Engraving and Observations Upon Sundry Processes of Photographic Engraving.” Although the paper was submitted to the British Association for the Advancement of Science, it was ultimately deemed inadmissible by the Chairman and never presented to the organization. Dallas filed for another patent in May of 1866 and was again refused but moved ahead with his own company, advertising the Dallastype and Dallastint as cheap first class engraving, one shilling per square inch. A reliable substitute for wood engraving, faithfully reproducing in any size the artist’s or other original specimens for six stamps.
Dallas wrote a letter to the British Journal of Photography, published in the March 5, 1875 issue, to protest Pretsch’s claim of developing photogalvanography. I had been the founder and organiser of the Photogalvanographic Company,” he claimed, “and had been robbed— I used the word deliberately—of the fruits of ray brain and hand labour by Mr. Paul Pretsch.
Later that year, in need of money, he tried to sell the process, publishing Proposal for Divulging the Dallastype Process of Photographic Engraving to Five Hundred Subscribers, or more, at £20 each ([London]: Duncan Campbell Dallas, 1875). Dallas went on to publish a facsimile of the 1623 Shakespeare First Folio and then, several portfolios of Walter Crane’s illustrations for individual plays.  
 Princeton https://graphicarts.princeton.edu/2016/01/22/what-is-a-dallastype/ Graphics Arts blog citesd 02/23/23
 Hanson, David. Checklist of photomechanical processes and printing 1825-1910, 2017 p. 37