Best known for his church buildings in the Gothic revival style, Blanc was also a keen antiquarian who oversaw meticulously researched restoration projects.

Blanc attended George Heriot's School, winning the dux medal in 1859, and was then articled to the architect David Rhind.

While working for Rhind, he attended classes at the School of Art and Design, where he met Thomas Ross, and became interested in medieval architecture.

Secular work includes Mayville Gardens in Trinity, Edinburgh, a pleasant and quirky Victorian cul-de-sac with a low terrace of ornate houses on each side (1881).

Bangour Village Hospital, West Lothian, was a competition win in 1898, and he designed the former Bernard's Brewery buildings in Gorgie (1887).

From 1893 to 1898 his nephew, Louis David Blanc (1877-1944), also trained under him (working largely on the Coats Memorial Church in Paisley).

[4] In 1910 he was appointed to a Royal Commission which oversaw British involvement in International Exhibitions held in Brussels (1910), Rome (1911) and Turin (1911).

He was buried in Warriston Cemetery in its lower section, just south of the vaults, southeast of the monument to James Young Simpson.