The Precision of the Miniature To look at the work of John S. Porter is to confront the disciplined reality of early nineteenth-century American portraiture. He was a miniature painter, a specialist working within the tight, unforgiving constraints of ivory. His career, active between 1822 and 1834, reflects a period when portraiture was a matter of intimate scale and intense technical control. He did not deal in grand canvases; he dea…