Clark began teaching at
University College London in 1962 as an assistant lecturer. He was appointed
Sir William Ramsay Professor in 1989, and served until retirement in 2009. He served as the dean of science from 1988 to 1989 and later as head of the chemistry department from 1989 to 1999. Clark died in London on 6 December 2018.
Artwork authentication In 1992, Clark was asked to develop a non-destructive technique to analyze the chemical composition of a painting in such a way to be able to spot art forgeries. He had since developed the use of
Raman spectroscopy as an important tool for use in the fields of artwork authentication, conservation, and preservation. ==Awards and honours==