Celebrations of city streets, tranquil vistas of the countryside and seashore, enchanting images of the leisured classes in domestic interiors or at fashionable Parisian caf s - the work of the Impressionists gives pleasure to art lovers everywhere. But while Impressionism today may appear natural and effortless, contemporaries were shocked by the loose handling of paint and the practice of painting out-of-doors. In defiance of the conservative...