Gwen John at the National Museum, Cardiff

Gwen John at the National Museum in Cardiff.

In contrast to her life story which is fascinating and exciting, John's body of work is suffused with an atmosphere of harmony and serenity. Waldenar Janusczak explains her art in this way: 'Have you ever visited a Japanese rock garden? The finest ones consist of nothing but an expanse of raked pebbles surrounding a plain rock. The idea is that the plainness of the rock aids and prompts contemplation. Well, Gwen John's portraits are like that. The simple monochrome background functions as the raked pebbles, while the calm, unmoving sitter becomes the central rock. It's a zen thing' .

Concentrating almost exclusively on interior settings and portraits, more precisely portraits of women, John captures the calm of the represented moment. She painted slowly and with a reduced palette, two facts that symbolise the quiet dialogue between the sitter and the artist. Her oil paintings concentrate on seated, often anonymous, women in a three-quarter view. She captured emotions and moods.

The Japanese Doll, 1920s, (oil on canvas)

The cool grey palette used for this work is typical of Gwen John's still-life paintings from the 1920s. It is set in the artist's studio in Meudon. Many of the objects in the picture are familiar studio props and they appear frequently in John's work.

Mere Poussepin Seated at a Table, mid-1910s (oil on canvas)

Gwen John turned to God after her relationship with Rodin ended. In each ease, her love was fierce and imploring. By 1912 she had begun instruction in the Catholic faith. She formed an association with the nuns of the Meudon Chapter of the Order of the Sisters of Charity of the Holy Virgin of Tours.

In 1913, on discovering John was a painter, the nuns commissioned her to paint the mother superior who founded the convent. And then they commissioned 12 more - one for each room of the convent, so that Mere Marie Poussepin would be always with them. For Mere Poussepin was dead. She had died two centuries before and John was working entirely from a likeness on a prayer card.

The portrait reflects a strong, intelligent, warm and collected woman. With as little decorum as possible and a reduced choice of tones, John captures the very essence of what she thinks a mother superior should represent. The art itself is as complex as ever - that pale luminosity partly achieved by using chalk in the primer as well as the paint, each brushstroke half-concealing the next so that you can scarcely see how it is done.

Girl in Profile, 1910, (oil and chalk ground on canvas)

This model sits before a simple interior. This was typical of John's portraits. The sitter is anonymous, but appeared in several paintings by John. The artist originally painted a mauve ribbon in her hair, but later scratched it out. James McNeill Whistler remarked that John showed a fine 'sense of tone'. Tone, rather than character, is the main focus of this work.

Girl in Green Dress, 1920s, (oil on canvas)