With Great Art making an impact on ITV, the Exhibition on Screen team are clearly on a roll and director-producer Phil Grabsky maintains the momentum with Cézanne: Portraits of a Life, which explores a show that opened at the Musée d'Orsay in Paris and will remain at the National Portrait Gallery in London until 11 February. As always, the combination of exquisite close-ups and expert opinion sheds fresh light on the artist and his work, while Brian Cox's narration captures the sense of curiosity that helped set Paul Cézanne apart from his fellow Impressionists.

Following restless tours of Atelier Cézanne in Aix-en-Provence and the exhibition, Dr Nicholas Cullinan (the Director of the National Portrait Gallery) and Laurence de Cars (Director of the Musée d'Orsay and the Musé de l'Orangerie) explain the origins of the first show to focus on Cézanne's portraits since 1910. Co-curators Mary Morton, Xavier Rey and John Elderfield suggest that, while Cézanne was a master formalist who specialised in still lifes and landscapes and didn't think of himself as a portrait painter, his pictures of the people close to him make it easier to trace his artistic evolution. Yet, Philippe Cézanne insists that his great-grandfather was more interested in keeping busy than in living up to his reputation as the `father of modern art'.

Over a lingering close-up of `Self-Portrait' (1862-64), we hear extracts from letters that Cézanne wrote in the late 1850s to Émile Zola, his former classmate at Collëge Bourbon. One recalls seeing a pretty girl named Justine emerge from the dressmaker's shop where she worked, while another laments being browbeaten by his banker father, Louis-Auguste, to study the law rather than art. Bruno Ely (Director of the Musée Granet) reveals that Aix-en-Provence was, in this period, still essentially a medieval town, whose gates were locked each night and he stresses the depth of the friendship forged during what was an idyllic childhood.

Zola had already left for Paris and, in 1861, he encourages Cézanne to come to the capital and spend his mornings working with a model and his afternoons studying the Old Masters in the many museums. He notes that this will leave them evenings free to enjoy themselves and, if the fancy takes him, he could always knock off a quick canvas during their weekend expeditions into the surrounding countryside. De Cars notes that Cézanne considered the Louvre to be an open book, where he first discovered modern works like Gustave Courbet's `A Burial At Ornans' (1849-50), which taught him the sense of honesty that would later inform `The Card Players' (1890-95) and `The Gardener Vallier' (1905-06).

It took Cézanne a while to get into a routine, however, as he informed fellow artist Joseph Huot that he spent a lot of his time mooching around. But Zola tells Baptistin Baille (the third member of Les Trois Inséperables) about a portrait sitting and comments on how angry Cézanne became when he couldn't catch the effect he was looking for. But he really let his fury rip in a letter to Count de Nieuwerkerke, in which he complains about his exclusion from the Salon exhibition and declares those who select the paintings to have no right to judge his work.

De Cars suggests that Cézanne struggled to find his niche in Paris, as he was regarded as something of a grumpy southern oaf on the periphery of Éduouard Manet's circle. Denis Coutagne (President of the Paul Cézanne Society) points out that he regularly returned to Provence, where he was regarded as a sophisticate, who could read Latin poetry and enjoyed music and writing verses of his own. He was also under less pressure to paint at the Bastide du Jas de Bouffan, the 18th-century residence of the town's military governor that had been acquired by Louis-Auguste in 1859. Cézanne had a studio there and it would remain a favourite bolthole until the death of his mother, Anne, in 1897.

Writing to Camille Pissarro in 1866, Cézanne concedes that his family can infuriate him, but he is never short of someone to paint. We see a portrait of his sister Marie, as well as `Uncle Dominique in Smock and Blue Cap' and `Uncle Dominique in Profile' (all 1866-67). Artist Antoine Guillemet enthuses to Zola about `The Artist's Father Reading L'Evénement' (1866) and jokes about how short-tempered he is with the locals who come to look at his paintings. Morton explains that he used a palette knife and wide brushes to achieve the rough `couillarde' style that he hoped would make a statement at the Salon. She also reveals that he changed the paper that Louis-Auguste is reading from Le Siècle to L'Evénement' because it had just published Zola's defence of the avant-garde and Cézanne wanted to pay tribute on canvas to both his father and his friend. In fact, it was only accepted by the Salon in 1882, by which time `Achille Emperaire' (1866-67) had also been rejected,

Over images of `Antony Valabrègue' and `Paul Alexis Reading a Manuscript to Émile Zola' (1869-70), we hear letters from Cézanne to musician Heinrich Morstatt and friend Justin Gabet about his frustration at not being taken seriously. Xavier Rey highlights the influence on the latter picture of Manet's `The Fife Player' (1866) and `The Balcony' (1868) and notes that the 1868 portrait of Zola also echoes Manet's style. As he states in a letter to Pissarro, he is happy to be considered among the emerging Impressionists, as they have started to sell well through Paul Durand-Ruel. Yet, as he informs his mother around the time he painted `Self-Portrait, Rose Ground' (c.1875), Cézanne felt no sense of inferiority and, indeed, rates himself better than the majority of the imbeciles who keep being favoured by the Salon hierarchy.

As Elderfield shows in `View From Jas de Bouffan' (1875-76), Cézanne has adopted a new style that relies on a lighter palette, smaller `constructed' brushstrokes and a coloured plane that allows him to convey atmosphere without pandering to traditional forms of perspective. Bruno Ely calls this a transitional painting, as the tree in the right foreground is less innovative than the fields dominating the rest of the canvas, which are more suggestive of the space being depicted. But there is a grimness to Cézanne's expression in `Self-Portrait' (c.1875), as the Impressionists are experiencing something of a backlash and he concedes to Zola in a letter from 1877 that times are hard (which means he must have been particularly grateful for the stipend he received from Louis-Auguste).

Refusing to be downhearted, Cézanne started to build on the Impressionist legacy and De Cars claims that he sought to impose a personal slant on the means of representation in items like `Landscape Near Paris' (c.1876) and `Still Life With Open Drawer' (1877-79), which remove the superfluous and ephemeral to achieve the emphasis on essence and structure that characterises his definitive style. She notes that Pissarro was striving towards the same goal and that his influence cannot be neglected.

By this time, Cézanne had fathered a son with Hortense Fiquet, who is seen in `Madame Cézanne in a Striped Dress' and `Madame Cézanne' (both 1885-86). However, he knows that his father will disapprove of the liaison and tries to keep it secret. But Louis-Auguste discovers the truth on opening a letter addressed to Paul and wrote to tell him that he was cutting his allowance, as he only had himself to provide for. Fortunately, Zola came to the rescue and, over a shot of `Victor Chocquet' (1877), Cézanne admits to the novelist that the sitter has let the cat out of the bag and that relations with his father have sunk to an all-time low. He is soon reduced to asking for loans and, yet, as we see portraits of Paul, Jr. from c1880 and 1883 and `Madame Cézanne Sewing' (1877) and `Madame Cézanne in a Red Armchair' (c.1877), it's clear that he had found a wife who gave him the freedom to paint and continued to take care of him even though she had to move to Paris on 22 separate occasions during their time together.

Elderfield dismisses speculation that the partnership was unhappy and suggests that people have read too much into Hortense's impassive expressions in her portraits, as well as Cézanne's own demeanour in `Self-Portrait' (1880-81) and `Self-Portrait in a White Bonnet' (1881-82). But, while he tells Zola of his domestic travails in a series of letters over `Towards Mont Sainte-Victoire' (1878-79) and `The Mill on the Couleuvre Near Pontoise' (1881), Cézanne seems pleased with his efforts to refine his new style, as he thrived on meeting the challenges that nature poses. Moreover, he is determined to recognise his son and make him co-beneficiary with his mother of his will (if only to stop his sisters getting hold of his money).

As we see `Self-Portrait' (1885) and `Self-Portrait With Beret' (1898-1900), Rey claims that these images provide key pointers to how Cézanne came to view himself as a man and as an artist. De Cars compares his use of self-portraits to that of Rembrandt van Rijn, as he reveals hints about his personality and mindset, while appearing to be withdrawn and guarded. He seems more relaxed, however, in `Self-Portrait With Bowler Hat' (1885-86) and `Self-Portrait With Palette' (1886-87), as he had just inherited a substantial sum from his father, which meant that no longer needed to produce saleable works in order to survive and could follow his own star. Rey finds the latter canvas particularly remarkable, as this metaphor for painting plays with past and present notions of representation and he highlights the positioning of the palette within the various planes.

Letters to art critic Octave Maus and Hortense's friend Marie Chocquet are heard over `Madame Cézanne' (1886-87), `The Artist's Son' (c1885-90) and `Madame Cézanne in Blue' (1886-87) suggest a degree of contentment, as the family spends time in Switzerland and Marseilles and Cézanne produces landscapes like `Mont Sainte-Victoire' (c.1890). His wife remains a favourite subject, however, as is clear from three portraits of her in a red dress seated on a yellow chair, dated 1888-90, Rey opines that this trio almost reduces Hortense to an object in a still life, while De Cars avers that Cézanne was straining to convey the essence of a sitter in the same way that Claude Monet was in a race to capture the light on cathedrals and haystacks. However, he did occasionally hire professional models like Michelangelo Di Rosa and Morton explains how `Boy in a Red Waistcoat' (1888-90) was inspired by Mannerist items like Agnolo Bronzino's `Portrait of a Young Man' (c.1530) and Jacopo Pontormo's `Portrait of a Halberdier' (c.1528-30), which Cézanne had seen in the Louvre.

Morton notes in this paean to adolescence how Cézanne starts with solid forms on the left-hand side of the image before allowing it to become more abstract as the eye wanders. He repeated this gambit in still-lifes like `The Kitchen Table' (1888-90), as he shows that solid surfaces can be rendered in variations of colour, shape and shade.

Following a brief digression, in which Cullinan explains why it's fitting that the exhibition should be coming to the National Portrait Gallery at a time when selfies are all the rage, the story resumes with a letter from Monet to art critic Gustave Guffroy lamenting the fact that Cézanne has too few supporters and is so racked by self-doubt that he has not been credited for his talent. After a shot of `Woman With a Caftière' (c.1895), we hear Guffroy appraising his own portrait (1895-96), which he bitterly regrets was left unfinished because Cézanne lost confidence in his approach. In 1895, he writes to Monet to justify his decision to return to Aix and search for his style away from the prying eyes of his detractors. He also informs poet Joachim Gasquet, over views of `The Smoker' (1893-96) and `Man With Pipe' (1891-96), that he resents having his private life raked over by scoundrels like Guffroy when he is trying to earn an honest living as a painter and have the odd quiet drink with friends like sculptor Philippe Solari.

Cézanne continued his diatribe against the critics in a letter to Gasquet, in which he challenges their assertion that he should be depicting nature in an authentic manner in paintings like `Bibémus' (1894-95) and `Bibémus Quarry' (c.1895). But he could also be encouraging, as in a missive to author Émile Solari, in which he hopes that he finds a sturdy companion in his new wife, as he knows how difficult it is to create. He also breaks the news of his own mother's death and his sombre mood is reflected in one of his last self-portraits, showing him wearing a beret, and in `Man With Crossed Arms' (c.1899). Yet, while he found it difficult to make friends back in Aix, he told poet Louis Aurenche that he had no intention of giving up art, as it is the most intimate form of communication he knows.

In 1902, Cézanne told Gasquet that he detested all living painters with the exception of Monet and Pierre-Auguste Renoir. He continued to produce striking works like `Seated Peasant' (c.1900-04) and maintains a close friendship with art dealer Ambroise Vollard, who had mounted his first solo exhibition in 1895 and whom he had painted in 1899. Bruno Ely recalls that Vollard had to endure 115 sessions for this picture and, even then, Cézanne left two unpainted squares on his hands, which he had intended to complete at the Louvre if the inspiration struck him. Philippe Cézanne similarly discusses the bond between the artist and his son, who managed his day-to-day affairs after Cézanne had agreed to sell Jas de Bouffan to help provide for his sisters and custom built his own studio on the Chemin des Lauves. While writing to artist Charles Chamoin, Cézanne hinted that his son wasn't the brightest of fellows, but he acknowledges his gratitude for his efforts on his behalf.

Over paintings from c.1902 and 1902-04 of Mont Sainte-Victoire. Cézanne also tells Chamoin that aspiring artists should study the Old Masters in the Louvre and then allow themselves to respond to the promptings of nature when they work. He informs Aurenche and artist Émile Bernard that it takes a lifetime to come to any sort of understanding of one's instincts when standing at an easel and shots of `Château Noir' (c.1900-04), `The Big Trees' (c.1902-04) and `Rocks and Trees' (c.1904) are used to illustrate his suggestions on the use of colour and texture to capture the ambience of a place. In his correspondence, Cézanne also reminds us that art is only appreciated by a small coterie and that painters should never allow themselves to be discouraged by critics, as they rarely know what they are talking about.

Rey declares that Cézanne provides the link between 19th-century art and such future titans as Pablo Picasso, Amedeo Modigliani and Alberto Giacometti, while Elderfield considers him the most important portraitist since Rembrandt, as items like `Alfred Hauge' (1899) and `Portrait of a Man' (1898-1900) were much more than physical representations, as he captured the essence of humanity. De Cars says he was a painter's painter, as he isn't always easy to fathom and requires the viewer to engage fully with the image. She also asserts that he was ahead of his time and was a modern artist before the concept had even been dreamt up.

As we see `Portrait of a Woman' (c.1900), `Seated Woman in Blue' (1902-04) and `Portrait of a Peasant' (1904-06), Cézanne confides in a letter to his son that he often finds it too hot to paint and that he has been plagued by bronchitis. Complaining that the heat benefits nobody but the beer sellers, he remains excited by finding new ways to paint familiar subjects, like the Gardener Vallier. In his last letters before his death on 22 October 1906, he informs his son that most of their compatriots are idiots and laments that he doesn't have the richness of colour to realise subjects to his satisfaction. But, most poignantly, he wishes that time didn't pass so quickly, as there is still so much he has to do.

Ending rather abruptly with the dates of the shows at the Musée d'Orsay, the National Portrait Gallery and the National Gallery of Art in Washington, DC, this is an intimate and enthralling overview of what many would consider a niche aspect of Cézanne's oeuvre. It's tricky trying to base a case for Cézanne as the father of modern art on his portraiture and Grabsky draws on a number of celebrated landscapes in the final reel. But he and his erudite and enthusiastic specialists succeed in showing how he provides a link between Rembrandt and the Cubists through his ideas on colour, structure and perspective. A little more might have been said about his relationships with his parents and Hortense, while a number of correspondents are cited with little or no contextual reference. It might also have been appropriate to mention Cézanne's later reliance on Catholicism and the reclusive nature of his existence after he was diagnosed with diabetes in 1890.

However, this is far more measured and focused than Danièle Thompson's overwrought biopic, Cézanne and I (2016), which starred Guillaume Canet as Émile Zola and Guillaume Galliene as his former classmate. As always, the cinematography of Grabsky, David Bickerstaff and Hugh Hood is of the highest order, with the shots of the narrow streets of Aix-en-Provence being particularly evocative. Clive Mattock's editing and Asa Bennett's score are also spot on, while Brian Cox capably conveys Cézanne's shifts between conviction and confusion, as he questions his own capabilities and condemns his foes in letters that are an essential companion to the self-portraits.