The swift changes of light and colour on the same subject, observable through the practice of painting en plein air, are immediately captured by the Impressionist painter and reproduced instantaneously on canvas. This can be clearly observed in the series by Monet, such as the Cathedrals and the Haystacks, or the more recent ones like the Waterloo Bridge and the Grand Canal. As stated by Sisley, effectively anticipating the behavior of the Post-Impressionists, there are no predefined colours, as each colour is an autonomous phenomenon and strictly depends on the colours adjacent to it; in this sense, shadows cannot be black, but rather blue, purple, indigo…
The interest of the Impressionists in the changing colours of subjects based on weather conditions extends to the representation of seasons and the study of the phenomenon of refraction of sunlight, which changes in intensity according to the time of year. Observing the works of Monet, Sisley, Renoir, Pissarro, and other minor Impressionists, it is clearly visible how each season is linked to a particular palette:
- Spring is identified by delicate yet vivid colours, such as the dashes of colour representing the many blossoming flowers in Renoir’s ‘Path in the High Grass’ (circa 1874).
- Summer, characterized by bright, warm, dazzling colours, or by cold but vivid blues and greens, and sharp shadows like those of Monet’s ‘Haystacks in the Sunlight, Morning Effect’ (1891).
- Autumn, on the other hand, is distinguished by reddish tones, oranges, browns, and muted greens, poetically portrayed in Sisley’s ‘Path at Louveciennes’ (1873).
- Finally, Winter, with its cold and desaturated colour palette combined with the dazzling presence of white, as seen in Sisley’s ‘Place du Chenil à Marly, Snow Effect’ (1876) or Camille Pissarro’s ‘White Frost’ (1873).”