Prior to the Impressionists, other painters, notably such 17th-century Dutch painters as Jan Steen, had focused on common subjects, but their approaches to composition were traditional. They arranged their compositions in such a way that the main subject commanded the viewer's attention. The Impressionists relaxed the boundary between subject and background so that the effect of an Impressionist painting often resembles a snapshot, a part of a larger reality captured as if by chance. Photography was gaining popularity, and as cameras became more portable, photographs beame more candid. Photography inspired Impressionists to capture the moment, not only in the fleeting lights of a landscape, but in the day-to-day lives of people.

The rise of the impressionist movement can be seen in part as a reaction by artists to the newly established medium of photography. The taking of fixed or still images challenged painters by providing a new medium with which to capture reality. Initially photography's presence seemed to undermine the artist's depiction of nature and their ability to mirror reality. Both portrait and landscape paintings were deemed somewhat deficient and lacking in truth as photography "produced lifelike images much more efficiently and reliably".

In spite of this, photography actually inspired artists to pursue other means of artistic expression, and rather than competing with photography to emulate reality, artists focused "on the one thing they could inevitably do better than the photograph – by further developing into an art form its very subjectivity in the conception of the image, the very subjectivity that photography eliminated".The Impressionists sought to express their perceptions of nature, rather than create exacting reflections or mirror images of the world. This allowed artists to subjectively depict what they saw with their "tacit imperatives of taste and conscience". Photography encouraged painters to exploit aspects of the painting medium, like colour, which photography then lacked; "the Impressionists were the first to consciously offer a subjective alternative to the photograph"

MORE MASTERPIECES (paintings and plastic art)

• Short, thick strokes of paint are used to quickly capture the essence of the subject, rather than its details. The paint is often applied impasto.

  Colours are applied side-by-side with as little mixing as possible, creating a vibrant surface. The optical mixing of colours occurs in the eye of the viewer.

• Grays and dark tones are produced by mixing complementary colours. In pure Impressionism the use of black paint is avoided.

  Wet paint is placed into wet paint without waiting for successive applications to dry, producing softer edges and an intermingling of colour.

  Painting in the evening to get effets de soir - the shadowy effects of the light in the evening or twilight.

  Impressionist paintings do not exploit the transparency of thin paint films (glazes) which earlier artists built up carefully to produce effects. The surface of an Impressionist painting is typically opaque.

  The play of natural light is emphasized. Close attention is paid to the reflection of colours from object to object.

• In paintings made en plein air (outdoors), shadows are boldly painted with the blue of the sky as it is reflected onto surfaces, giving a sense of freshness and openness that was not captured in painting previously.