Georges Seurat (1859-1891), The Channel at Gravelines, Evening, 1890, oil on canvas, 65.4 x 81.9cm, The Museum of Modern Art, New York, gift of Mr and Mrs William AM Burden

THE Italian-born anarchist, gallerist, and art critic Félix Fénéon coined the term Neo-impressionism in 1886 for the movement led by Georges Seurat.

Eighteen months younger than Seurat, and having moved to Paris, he would champion the works, and a painting of the entrance to the port of Honfleur, where the Seine meets the Channel, was gifted to him by the artist and can be seen in a new show at the Courtauld Gallery.

Fénéon would outlive Seurat (1859-1891) by more than half a century and the fact that the artist died aged just 31 adds not just poignancy to the exhibition* but a realisation of how important and spectacular these works are.

Seurat and the Sea is the first exhibition dedicated to his seascapes and first devoted to him in this country for almost 30 years. It features 26 exceptional paintings, oil sketches, and drawings, in an examination of Seurat’s ground-breaking style. He used dots of pure colour directly onto the canvas, the technique known as pointillism (variously chromoluminarism or divisionism).

Georges Seurat (1859-1891), La Maria at Honfleur, 1886, oil on canvas, 53 x 63.5cm, National Gallery, Prague

The Honfleur gifted to Fénéon is a loan from the Barnes Foundation in Philadelphia; but such is the pull of the Courtauld’s excellence, there are also loans from the Tate, V&A, and the National Gallery, London; the national galleries in Canberra, Washington, and Prague; the Museum of Modern Art, New York; the Musée d’ Orsay and Centre Pompidou, Paris; and others from Geneva, Tournai, Baltimore, Minneapolis, Saint Louis, Indianapolis, Kansas City, Otterlo; and from private collections too.

It’s a true privilege to see these together in a show that’s been many years in the making. Indeed, in all, Seurat left fewer than 50 canvases known to us.

Head of the Courtauld Dr Ernst Vegelin Van Claerbergen says in his foreword to an extensive show catalogue: “For an artist more commonly associated with modern Paris and its lively suburbs, it is surprising to learn that views of the Channel coast account for the largest single subject category in Seurat’s oeuvre.” The selection in the current show has “examples from each of Seurat’s five summer campaigns between 1895 and 1890”.

Senior Courtauld curator Dr Karen Serres writes that the fame of Seurat’s works such as A Sunday on La Grande Jatte and Bathers at Asnières has often eclipsed the major group of the seascapes on display here.

Georges Seurat (1859-1891), Seascape at Port-en-Bessin, Normandy, 1888, oil on canvas, 65.1 x 80.9cm, gift of the W Averell Harriman Foundation in memory of Marie N Harriman, National Gallery of Art, Washington DC

His “marines”, depicting ports and the open seas, “are an exploration of light in open spaces devoid of people”, she says. They enabled him to refresh his technique “at an elemental level” and they remained highly influential with the avant-garde after his death, she notes.

The Paris-oriented Seurat would escape to the coast for these breaks, he would make small oil sketches on wooden panels, and work up the larger canvases later.

There are some rare figures of people on the sand in one of the six paintings featuring Port-en-Bessin, Normandy, all from 1888.

There are 1885 works from Grandcamp, six in all from Honfleur, 1886, its lighthouse included; Le Crotoy, Downstream, 1889; and oils from Gravelines in 1890, with accompanying Conté crayon studies. And the Courtauld’s own The Beach at Gravelines, a small oil on wood panel, is also displayed.

Dr Serres sums up the “marines” as not formulaic but contemplative and meditative.

But, as the oil highlighted for the show publicity – Seascape at Port-en-Bessin – suggests, at times they are quite monumental.

• The Griffin Catalyst Exhibition: Seurat and the Sea is at the Courtauld Gallery, Somerset House, Strand, WC2R 0RN until May 17. See: www.courtauld.ac.uk