The Le Nain Brothers, 'Three Men and a Boy', about 1647-8

These three men are probably the painter brothers Antoine, Louis and Mathieu Le Nain: their noses and chins suggest a family resemblance. The costumes, with their broad collars, suggest a date of the late 1640s or early 1650s, but if this is a portrait of the brothers it cannot be later than 1648 – the year Louis and Antoine died. Their deaths may explain why the painting was not completed.

This unfinished work gives us an insight into the artist’s painting process. The bodies, limbs and clothing were initially sketched in with rough brown outlines. The face of the man on the right reflects an earlier painting stage, as shown by his sketchy appearance and pale complexion. Detail and texture was added later, as can be seen in the delicate line of buttons on the sleeve of the man on the left, the shimmery satin fabric and the wavy hair. There are different levels of finish in the painting: the artist seemingly worked from left to right, painting faces first then the lovely jacket with its satin sheen, but not filling in the details of the other figures.

When the National Gallery acquired this work it was thought to be by a follower of the Le Nain brothers. It was previously called A Trio of Geometers because it had been overpainted, and geometrical instruments and a globe had been added in the right foreground. Cleaning in 1968 removed these items and revealed that the picture is unfinished.

The picture reveals part of an earlier composition: the head of a boy on the right and the colourful blue and yellow drapery emerged when the overpaint was removed. The results of the cleaning meant that the painting is now thought to be a genuine Le Nain. X-ray images have also revealed that this scene was painted over the portrait of a seated woman. It was common for canvases to be reused in the brothers' studio. .

The National Gallery owns several other works attributed to the brothers: The Adoration of the Shepherds and Four Figures at a Table.