His very careful and loving representation of Islamic architecture, furnishings, screens, and costumes set new standards of realism, which influenced other artists, including the leading French Orientalist painter Jean-Léon Gérôme in his later works.
Unlike many other Orientalist painters who took a salacious interest in the women of the Middle East, he "never painted a nude", and his wife modelled for several of his harem scenes.
[2] These, with the rare examples by the classicist painter Lord Leighton, imagine "the harem as a place of almost English domesticity, ... [where] ... women's fully clothed respectability suggests a moral healthiness to go with their natural good looks".
David Roberts, who became the other leading British Orientalist, mainly through his lithographs, was in Spain and the Middle East at the same time as Lewis, though the two rarely met, and William James Müller had been in Cairo in 1838.
[16] He wrote to a colleague: "Generally in spite of all my hard work, I find water colour to be thoroly [sic] unremunerative that I can stand it no longer—it is all, all always, rolling the stone up the hill—no rest, and such little pay!
[18] In his technique, "Independently of the Pre-Raphaelites, Lewis had evolved a similar method, applying colour with a minute touch on a white ground to produce a glowing jewel-like effect".
[19] Lewis became an Associate of the Royal Academy (ARA) in 1859 and a member (an RA) in 1865, and was President of the Society of Painters in Water Colours from 1855, though this was just as he was abandoning the technique for oils.