found: Emerson, P. H. Pictures of East Anglian life, 1888: page iii ("The plates have been reproduced on copper from my original negatives by the Autotype Company, the Typographic-Etching Company and Messrs. Walker & Boutall")
found: Oxford Dictionary of National Biography (WWW), July 30, 2015:under Walker, Sir Emery, 1851-1933 (process engraver and typographer; in 1886, in partnership with Walter Boutall, "founded the firm of 'process and general engravers, draughtsmen, map-constructors, and photographers of works of art' known first as Walker and Boutall, later as Walker and Cockerell, and finally as Emery Walker, Ltd. Its office was at 16 Clifford's Inn ...The works were at a Georgian house not far from Walker's home in Hammersmith Terrace, London)
found: The process photogram and illustrator, July 1900, via Google Books, July 30, 2015:page 112 ("The partnership heretofore existing between Emery Walker and Walter Boutall, trading as Walker & Boutall, photo-engravers, Clifford's Inn and Hammersmith, has been dissolved as from June 30th. The business of Walker & Boutall will be continued by Mr. Emery Walker. We understand that Mr. Boutall will continue his connection with photo-engraving business as chairman of Vaus & Crampton, Ltd.")
found: photoLondon WWW site, July 30, 2015(under Walker & Boutall: partnership between Sir Emery Walker & Walter Boutall; studio: 16 Clifford's Inn, Fleet Street, City of London, 1887-June 1900 June 1900 -1903; succeeded by Walker & Cockerell; partnership dissolved June 24 1900 (London Gazette 1900, page 4318) - http://www.photolondon.org.uk/pages/details.asp?pid=8066