Musicologist and amateur photographer. Muir was born in Edinburgh into a family of piano-makers and music publishers. He trained as a pianist and, from 1826, he travelled in Europe studying music but also taking photographs.
He taught the piano and also continued the family instrument-making and publishing business from a shop on Waterloo Place in Edinburgh. As an amateur photographer his work included portraits, groups, street-scenes and landscapes. In 1841, he toured the west of Scotland with painter James Eckford Lauder (1811 - 1869).
He experimented with the calotype and carbon processes and the addition of various metals, such as copper, tin, gold and uranium, intended to produce different tones and more permanent images. The Scottish National Portrait Gallery in Edinburgh holds a significant collection of his photographs.
He was involved in arranging the visit of Frederick Chopin to Scotland in 1848, with London-based piano-manufacturer James Broadwood.
