Blackham, Dorothy Isabel (1896–1975), artist and teacher, was born 1 March 1896 in 4 Beechwood Rd, Rathmines, Dublin, daughter of Charles H. Blackham, chief cashier at Kingsbridge railway terminus, and Jane Ruthven Blackham (née Lowry) of Killyleagh, Co. Down. She was related on her father's side to the Wharton family of artists; her maternal grandfather was the antiquarian and crown prosecutor Thomas Kennedy Lowry (1811?–1872). She received her training initially at the RHA schools, where she was taught by Dermod O'Brien (qv) and where she developed a particular interest in poster design, after which she went on to study at the Metropolitan School of Art and in London at Goldsmith's College (1921–2).
Blackham had a prolific career as an exhibitor and contributed her work to shows throughout Ireland. She exhibited regularly with the RHA for thirty years from 1916; her work was also shown by the Ulster Society of Women Artists, the Watercolour Society of Ireland, the Arts and Crafts Society of Ireland, and (from 1924) at the Aonach Tailteann, where she was awarded medals in 1928 and 1932. Her 1936 exhibition at the Stephen's Green Gallery was followed by a second at 7 St Stephen's Green in 1943. Like her friend Mainie Jellett (qv), who was a significant influence, she became interested in the activities of the White Stag Group, with whom she exhibited on four occasions in 1940–41. A member of the Dublin Painters' Society, with whom she exhibited throughout the late 1930s, she was also associated with the short-lived Picture Hire Club (1941–2). During this period she experimented extensively with lino-cuts, executing large-scale prints of landscapes. Through her close friendship with Elizabeth (qv) and Susan Yeats (qv) she became a major collaborator with the Cuala Press, for whom she produced wood- and lino-cuts for illustrations and greetings-cards. She provided illustrations for the Cluna Press, the Irish Tourist Association, The Bell, and The Ideal Irish Home, and designed the cover for Rev. Myles V. Ronan's (qv) booklet The Boyne Valley and its antiquities (1936). Added to this was her work as a teacher in several Dublin schools, notably Alexandra College (1936–43) and the Hall School, Monkstown.
In 1944 she worked as assistant warden at the Gibraltarian Evacuation Camp in Derry. After her marriage to Elsner Stewart (1947), she moved to London, where she resumed her career as a teacher, and continued to exhibit under her maiden name. Her work was shown by the RA, Royal West of England Academy, United Society of Artists, and Royal Society of British Artists. In 1967 she and her husband returned to Ireland, settling in Donaghadee, Co. Down. Though her subject matter generally draws on Ireland for inspiration, most particularly the west and north, she also produced scenes of London and the Continent. Her RHA exhibits throughout the 1920s and 1930s include numerous Italian and French subjects, while in the postwar period she visited Portugal. Despite being afflicted by arthritis she continued to paint till her death in Donaghadee, 4 September 1975. Posthumous exhibitions of her work were held at QUB (1976) and the Neptune Gallery, Dublin (1977). She is represented at Dublin City Gallery The Hugh Lane, QUB, and the South London Art Gallery.