Houston’s first trip abroad was in 1953/4 on a scholarship from Edinburgh College of Art, to Italy when he was in the company of his friend and fellow student David Michie. They spent time in the great Renaissance Tuscan cities but John’s most productive subjects came from the hill towns of Orvieto and Anticoli.

In 1955 Houston was in Italy, Yugoslavia and Greece; in 1957, Spain: to Barcelona and Madrid via Paris. In the sixties Houston was in France most years, visiting Normandy and Brittany in 1961 but also Portugal, Holland and Germany. In 1969 he came to the USA for the first time at the invitation of Mr and Mrs Samuel Johnson of Racine, Wisconsin (of Johnson Wax fame). He was in Switzerland the next year and the year after and in Harris with David Michie in 1974.

On many short European trips he would be visiting exhibitions and collecting catalogues as well as thinking about painting. The eighties saw more extensive travel despite his teaching commitments at the College where he became Deputy Head of the Painting School in 1983: to New York in 1983 and the following year; to Japan for the first time in 1986 and again in 1987. After retirement from teaching he and Elizabeth Blackadder travelled even more, chiefly in Europe but with a final trip to Japan in 1993.

Houston was ten times a solo exhibitor at The Edinburgh International Festival between 1961 and his last show in 2008. He was an expressionist who could also evoke the subtle, particular character of place, but as with The Festival his vision and ambition always looked outward.