This portrait print was frontispiece to Forrest's 'Voyage to New Guinea and the Moluccas....' published in 1779, his account of explorative investigations of these islands that he undertook as an East India Company navigator in 1774-76, and for the Company. He had by then already then spent some time as a commander of East India 'country' ships: i.e. those trading solely between eastern ports, not from and to Britain. Of the three vesssels in the left background, the largest is probably the Philippine 'garay' of about ten tons burthen which he commisssioned for the expedition and called the 'Tartar', manned by a Malay crew of 18, with two smaller local craft which are probably also those shown given that he published the print himself. It includes what are presumably his personal arms at the bottom, with an additional caption lower right giving his age in 1779 as 50 and that he was a midshipman in the Navy in in 1745 ('Aetat 50 Midn in the Navy in 1745').

Forrest seems to have been in the Navy, mainly in Eastern service, to just before 1762 which (by his own account) was about the time he first gained a local East India Company command. He is shown in civilian dress with his hand on a chart of the area he investigated. Nothing is known of his family, exact date or place of birth or of death, but he is thought to have died about 1782, still in India.