The front-facing portrait is one of fifty-three drawings by Johan Zoffany, executed during the 1790's for his friend in India. Trois crayons is a drawing technique using three colours of chalk: red, black, and white.

In Wolff's Album we have two portraits of Claude Martin - the portrait in profile bearing Zoffany's comment "This I Find Of Wery Leick". These may have been executed during his stay with Martin in Lucknow or more likely in England and after studies from India.