The dominating style in late eighteenth century British portraiture is known as "Grand Manner." Some credit the invention of the style with Joshua Reynolds refined and defined the style in his Discourses on Art and would discuss it in his lectures at the Royal Academy. Reynolds actually would refer to it as "great style" or "great style" but names were not important, it was the concept of the style.
1. Paint a full length life size or larger.
2. Put the sitter in a Classical pose (extra points for a gesture)
3. Paint an Arcadian landscape, more fantasy than reality.
4. Include a Classical prop: urn, fragment of architecture, or even Laocoon statue (if you are in Rome)
5. Dog is a charming touch but optional