Louis XV of France

surface prep

The artist worked on canvas, which requires a specific preparation for pastel. Unlike oil painting where the sizing protects the support (Source 6), pastel requires a 'tooth' to hold the pigment. De La Tour likely used a sized canvas with a slight texture or a specialized ground to allow the pastel to adhere. The preparation must ensure the surface is not too smooth (which would cause sliding) nor too rough (which would break the delicate pastel sticks).

underdrawing

De La Tour’s technique was characterized by a 'delicate but sure touch' (Source 8). In pastel portraiture of this period, underdrawing was often minimal or integrated into the first layer of color application. The artist likely began with a light sketch using a neutral pastel or charcoal to establish proportions, but given the directness of the medium, the drawing phase would be brief and immediately followed by color application.

underpainting

Not applicable in the traditional oil sense. Pastel is an opaque, direct medium. However, the artist may have laid down broad masses of color first to establish the tonal structure, similar to the advice to 'deal with broad masses' before finishing (Source 3).

Simultaneous Contrast

Using complementary colors adjacent to each other to enhance the perceived intensity of each. The painter must perceive and imitate the modifications of light and color resulting from contiguous colors (Source 2).

Harmony of Contrast

Mixing colors with grey or using light tones of complementary colors to avoid monotony and crudity, especially in remote planes or when distinctness is required (Source 1).

Direct Pastel Application

Applying dry pigment directly to the surface without underpainting, relying on the opacity and texture of the pastel to build form and light.