Giovanni Battista Cima da Conegliano, 'The Incredulity of Saint Thomas', about 1502-4

The rich colours of this large altarpiece were designed to make maximum impact. It was commissioned by the Scuola di San Tommaso dei Battuti, a confraternity which ran four hospitals in Portogruaro, north of Venice, and was dedicated to Saint Thomas. It shows the moment that the doubting saint was convinced of the truth of the Resurrection.

According to the New Testament, after his crucifixion Christ appeared to his disciples and showed them his wounds. Thomas was absent and doubted what had happened: ‘Except I shall see in his hands the print of the nails, and put my finger into the print of the nails, and thrust my hand into his side, I will not believe.’ Christ appeared again eight days later and invited Thomas touch him (John 20: 19–27). In this painting we see Saint Thomas place his fingers in the wound in Christ’s side, surrounded by the astonished apostles: the young and fair-haired John the Evangelist in blue, immediately on Christ’s right, and the balding Saint Peter, with short curly beard and hair, on his left.

The painting is signed and dated in the small cartellino on the right: Joanes Baptiste Coneglane[n]sis / opus 1504 (‘the work of John Baptist of Conegliano 1504’). The date is a later addition. The larger cartellino in the centre, below Christ’s feet, gives the names of the officers of the scuola.

Unusually, we know a great deal about how this painting was made from the confraternity’s accounts and minutes. The governing committee voted to commission an altarpiece for their church of San Francesco at Portogruaro on 28 May 1497, stipulating that it was to be a painted altarpiece, not a sculpted one, and done as cheaply as possible. Presumably Cima da Conegliano was approached soon afterwards. Payments seem to have commenced in 1502, though he may well have begun work on it before this.

In 1504 the altarpiece was reported as nearly ready but deliberately left unfinished by the artist as he had not been paid. It was completed, shipped to Portogruaro and installed later that year – the accounts include payments for a case for transporting it, for the porters who carried it to the site and a tip for Cima’s assistants. The artist was still owed more than half his fee when the altar was delivered; he eventually had to resort to legal action and wasn't paid in full until 1509. A 1584 visitation recorded that the painting was over the first altar on the right as you went into the church, which is possibly why the light falls from the right instead of the left: if it was at the west rather than the east end, the light would have fallen on it from the west window.

The jewel-like colours and the way the draperies are modelled owe much to the work of Giovanni Bellini, the great Venetian interpreter of light and colour. Cima was a master of the technique of building up light and shade by the application of layers of glazes. In the first stage, the draperies would have been painted as broad, flat areas of colour. The differences in tone that we see as folds and creases were achieved by variations in the thickness of the glaze. Venice at this time was a centre of the pigment trade and Cima has here used an exceptionally wide palette of pigments in different combinations.