Brocas is said to have been self-taught as an artist. His primary interests were in engraving and landscape painting, mostly in watercolour. As an engraver he was noted for his portraits and caricatures of Dublin figures of the late 18th century, many of which were published in the Hibernian Magazine. He also worked as a cartoonist and/or engraver for Exshaw's Magazine, a repackaging of material from English magazines with some original material of Irish interest. Illustrations in this period could only be printed from woodblocks or copper engravings, and unless publisher John Exshaw had access to the original blocks or plates, reprinting cartoons would mean re-engraving them. Brocas is credited with a print of the great English cartoonist Thomas Rowlandson's "The Loves of the Fox and the