Buchanan works primarily in watercolour depicting architectural themes in broad washes. He trained at the Edinburgh College of Art from 1976-1980 and was awarded travel scholarships to the Middle East, North Italy and the Balkans and has travelled regularly throughout Europe to paint buildings and interiors from the Renaissance to the Baroque. He has worked on commissions for the National Trust and was invited by HRH the Prince of Wales to paint a series of interiors of Balmoral and subsequently at Highgrove. In 1988 he was commissioned by the House of Commons to paint four interiors in the Palace of Westminster.
Buchanan's paintings are in the Collections of HM The Queen, HRH Queen Elizabeth the late Queen Mother, the Palace of Westminster, the University of Edinburgh, the Bank of Scotland, the Royal Bank of Scotland, Flemings Bank, Deutsche Bank, the National Trust for Scotland, the National Trust for England and the House of Lords.