Born Glasgow, died in London. Painter in oil and watercolour of landscape, seascape and occasional portraits. Son of a lithographer. His subjects were mainly landscapes of the north east coast of Scotland, fishing villages and cliffs. Working first near Glasgow, he exhibited at the Glasgow Institute in 1873 and at the Royal Academy from 1875 onwards. Although mainly self taught, after moving to Paris in 1875 he studied for a short time at the Beaux Arts and at the Atelier Julian. From there he sent many plein air landscapes to the RA and other English exhibitions. Settled in London in 1881 and continued to sketch frequently in Holland, Belgium, France and Italy, touring India in 1891-2 and Japan in 1907. His seascapes and harbour scenes have been likened to those of Colin Hunter but his foreign scenes reflect more his Paris training. His work in watercolour is sometimes likened to that of Melville and although without that artist's talent as a draughtsman the technique is similar.
Most of Allan's compositions include the human figure though painted incidentally rather than as the focal point. He was particularly interested in depicting atmosphere and colour with the subject matter of secondary importance. A regular exhibitor in the French Salon, winning medals in 1899 and 1900 and an hors de concours. He was one of the first watercolourists to be influenced by the French Impressionists. His output was prolific and he exhibited over 1,100 works in his lifetime in Britain alone. In 1934 he executed a portrait of Lloyd George. Elected RSW in 1880, ARWS in 1887, RWS in 1886, VPRWS 19-8-1910. His work is represented in many art galleries.