While the use of colour to encode meaning in terms of sex/gender or devils is relatively unusual, there are other situations where colour conventions are employed in paintings. Among these are standards seen in religious paintings, such as those of the Virgin Mary.

In many paintings of the Virgin Mary, she’s shown wearing a cloak of ultramarine blue, although there are also examples of her wearing green, or a combination of red and green. In Sassoferrato’s The Virgin in Prayer, her cloak looks as if it was painted only yesterday rather than nearly four centuries ago. The choice of ultramarine may have originated from the fact that the pigment was weight-for-weight more expensive than gold, and visually even more stunning.

Dante Gabriel Rossetti’s painting of The Girlhood of Mary Virgin (1848–9) shows her embroidering with her mother Saint Anne, while her father Saint Joachim prunes a vine. Her red embroidery signifies the Passion to come, and the colour is often a symbol of Christ’s blood shed in the crucifixion. It was also adopted as the colour code for cardinals in the Roman Catholic church.

Raphael’s magnificent Portrait of a Cardinal from 1510-11 is notable not only for the lifelike modelling of flesh, but for his attention to the surface textures of the fabrics, something he had developed since his early days with Perugino. Three distinct fabrics are shown in the cardinal’s choir dress: the soft matte surface of the biretta (hat), the subtly patterned sheen of his mozzatta (cape), both in cardinal red, and the luxuriant folds of his white rochet (vestment).

With a limited range of colours available, it was inevitable that there were unfortunate conflicts, as red not only signifies the Passion and crucifixion, and cardinals, but the scarlet woman as a carnal red.

There are two origins proposed for the term scarlet woman: the earlier is the New Testament book of Revelation, in its characterisation of the Whore of Babylon in chapter 17, verses 4-5, where she’s described as being dressed in purple and scarlet, and decked with gold, precious stones and pearls. William Blake’s watercolour of The Whore of Babylon from 1809 follows this literally, although his purple has faded now.

Carolus-Duran’s Portrait of Mademoiselle de Lancey (1876) was exhibited at the Salon, and in its own way became infamous as ‘the lady with the red cushion’. Most of those who attended that Salon knew only too well that she was one of the great courtesans of the Belle Epoque, and could name many of her succession of rich lovers. The scarlets and crimsons and her direct wide-eyed gaze at the viewer left little to the imagination, and the critics were almost as merciless with Carolus-Duran as they had been in 1865 with Manet’s Olympia.

A few artists have used distinctive colour codes in other ways.

Félix Vallotton’s Andromeda Standing with Perseus (1907) shows the sea monster Cetus heading for a defenceless Andromeda, as hero Perseus charges to her aid through a cleft in the black sky. Each figure is colour coded: green for the sea monster, pink for the near-victim, and blue for the hero, against a straw-coloured sea.

Evelyn De Morgan’s Cadence of Autumn from 1905 shows five women in a frieze, against a rustic background. From the left, one holds a basket of grapes and other fruit, two are putting marrows, apples, pears and other fruit into a large net bag, held between them. The fourth crouches down from a seated position, her hands grasping leaves, and the last is stood, letting the wind blow leaves out from each hand. They wear loose robes that are coloured (from the left) lilac, gold, brown, green, and black, the sequence seen in nature.

Colour can be at its most important in multiplex narrative, to indicate each occurrence of an actor, so helping the viewer assemble each part of the story into a whole.

Masaccio’s Tribute Money (1425-8) contains three images of Saint Peter, and two of the tax gatherer, each carefully set and coherently projected into the same single view. Although each is spaced apart from the next, no pictorial device is used to separate them into frames, and they form multiplex narrative. This refers to the Gospel of Matthew, in a story in which Christ directs Peter to find a coin in the mouth of a fish so that he can pay the temple tax. In the centre, the tax collector asks Christ for the temple tax. At the far left, as indicated by Christ and Peter’s arms, Peter (for the second time) takes the coin out of the mouth of a fish. At the right, Peter (a third time) pays the tax collector (shown a second time) his due.

In the late nineteenth and early twentieth centuries, there were three dominant painters who flirted with Impressionism but retained conventional styles: Anders Zorn from Sweden, Joaquín Sorolla from Spain, and John Singer Sargent, an American expatriate who worked from studios in Paris and London. All three died in the 1920s, and this year we commemorate the centenary of Sargent’s death on 14 April 1925. This is the first in a series of six articles outlining his career with but a small and personal selection of his paintings.

Sargent was born to American expatriate parents in Florence, Italy, in 1856. He was educated at home and showed early skill in drawing. Already competent in watercolour at the age of 14, he saw many of the works of the great Masters during travels around Europe with his family. In 1874 he succeeded in gaining admission to the École des Beaux-Arts in Paris, where he was taught mainly by Carolus-Duran, and less by Léon Bonnat.

Although his initial enthusiasm was for landscapes, Carolus-Duran encouraged him towards portraiture, and his first significant portrait was accepted by the Salon in 1877. His talent was recognised by the critics, and he made friends with Julian Alden Weir and Paul César Helleu, who in turn introduced him to other leading artists of the day, including Degas, Rodin, Monet, and Whistler.

Sargent’s early style was realist, particularly in portraiture, and leaned towards Impressionism as seen in this painting of Fishing for Oysters at Cançale from 1878, but was quite distinct from the work of the leading Impressionists at that time. In the summer of 1878, John Singer Sargent had just completed his studies with Carolus-Duran, and went off on a working holiday to Capri, staying in the village of Anacapri, as was popular with other artists at the time.

Capri was still quite a select holiday destination then, and unspoilt. But getting a local model was tricky, because of the warnings that women were given by priests. History has proved those priests only too right in their advice. One young local woman, Rosina Ferrara, seemed happy to pose for him, though. She was only 17, and Sargent a mere 22 and just developing his skills in portraiture. Over the course of that summer, Sargent painted at least a dozen works featuring young Rosina, who seems to have become almost an obsession with him.

One, Dans les Oliviers, à Capri, above, he exhibited at the Salon the following year. A near-identical copy A Capriote, below, he sent back for the annual exhibition of the Society of American Artists in New York, in March 1879. The latter is now in the Museum of Fine Arts in Boston.

He also painted a pair of views of what was probably the roof of his hotel. In View of Capri, above, made on cardboard, Rosina stands looking away, her hands at her hips. In the other, Capri Girl on a Rooftop, below, she dances a tarantella to the beat of a friend’s tambourine. The latter painting Sargent dedicated “to my friend Fanny”, presumably Fanny Watts, who modelled for the first portrait that Sargent had exhibited at the Salon the previous year.

Rosina appears to have danced for Sargent again, for him to paint her in Portrait of Rosina Ferrara, above, as a precursor to his later paintings of Spanish dancers. But of all Sargent’s paintings of Rosina, the finest portrait, possibly one of the finest of all his ‘quick’ portraits from early in his career, is another painted in oils on cardboard: Rosina Ferrara, Head of a Capri Girl, below.

This he dedicated to “Hyde” (the artist Frank Hyde), and signed in 1878, while he was still on Capri. There are another couple of portraits he painted of a young woman during that summer on Capri. Although she’s in more serious mood, possibly even a little surly with ennui, I wonder if they also show Rosina Ferrara.

Sargent left Capri, eventually returning to Paris and his inexorable rise to greatness, fortune and success. But that wasn’t the end of Rosina’s modelling career, not by a long way. Frank Hyde, to whom Sargent had dedicated a portrait of her, painted his own version a couple of years later.

Sargent’s famous Portrait of Carolus-Duran (1879) is not only his personal tribute to his teacher, but when it was shown at the Salon proved the foundation of Sargent’s own career as a portraitist.

He continued to travel in Italy and Spain, where in 1880 he painted Smoke of Ambergris, demonstrating what was to come beyond mere portraits.