The Weekend's TV: The Impressionists: Painting and Revolution, Sat, BBC2<br/>Secrets of the Pop Song, Sat, BBC2

The Impressionists are, as Waldemar Januszczak confessed at the beginning of his new series, "terribly popular, terribly familiar, terribly commercialised".

The first element presumably explains why BBC2 has commissioned a four-part series in the first place, but the other two give the person who got the commission something of a headache. How do you restore to these paintings, so safe and comforting and well-loved, something of the impudent shock they generated when they were first exhibited? Candour about the problem was the first strategy here. Staggering through the doors of the Savoy, on his way to the hotel room from which Monet painted his famous views of the Thames, Januszczak delivered his opening lines from behind a stack of bags and boxes, the fruits of an Impressionist shopping spree in London that had netted him Impressionist pencil cases, jigsaws, tote bags, chocolates and a memorably ghastly shirt. Dropping them to the floor, he implicitly asked how it had come to this – the punks of the 19th century art scene reduced to mere decoration.

Assault from an unexpected direction was another strategy. The first thing you saw in The Impressionists: Painting and Revolution was a tube of crimson oil paint being washed in a tropical surf. It was a seductively enigmatic image and naturally its allure had to be blunted by the obligatory signage for the stupid that so many documentaries are now forced to display near the entrance. But once Januszczak had done his duty with the boilerplate text ("In this series we're going to be looking at the greatest art ever painted"), he could get back to teasing out the implications of that first shot. The tropical surf, it turned out, was on the island of St Thomas, the boyhood home of the painter Camille Pissarro, who "provided the glue that held the Impressionists together". And the tube of paint was a clue to a largely unsung hero of Impressionism, John Goffe Rand, an American portrait painter who ended up living in London. Rand didn't leave a mark on Impressionism through his art but through his invention – a collapsible zinc paint tube that kept pre-mixed pigment usable for much longer and enabled painters to head out into the open air.

There were other practical explanations for the novelty of the Impressionists' style. The invention of the metal ferrule, which meant that paintbrushes could have a flat profile, left its mark on their paintwork, and Januszczak visited a porcelain workshop to see how Renoir's apprenticeship as a plate-painter contributed to the feathery transparency of his painting. But he also explored the more familiar aesthetic genealogy, as a young group of painters found common cause in rebelling against the power of the academy and the deadly smoothness of salon style. Januszczak's own style has a kind of clattery, in-your-face manner that isn't a bad match for his subject here, and although not all of his conceits work (there was a lot of digging during a passage about Monet that didn't seem entirely justified by the artistic detail that had given rise to it), it's still preferable to the pompier style of more old-fashioned BBC documentaries. He finished with a minor coup – getting a camera inside the room in Nadar's studio where the first Impressionist exhibition was held – and a very engaging footnote. If Degas had got his way, the grouping would have been called the The Nasturtium, after one of his favourite flowers. If only Edgar had been a little more insistent we could be talking about Post-Nasturtianism these days.

Secrets of the Pop Song this week moved on to the anthem, a form apparently distinguished from the ballad by the fact that it's "not about you and me –it's about us". It seems a very broad category, encapsulating, according to this reading, Pulp's "Common People", Queen's "We Will Rock You" and a show tune like "You'll Never Walk Alone". To work one up from scratch, Guy Chambers joined forces with Noisettes. His rather understated diffidence did not entirely gel with their upfront manner, though he could hardly say he hadn't been warned. Shingai, the Noisettes' singer, has "Not for the faint-hearted" tattooed across her shoulders.

It's an odd enterprise, this – like pencilling a date in your diary so that you can be struck by lightning – but the series has been quite revealing about the nuts and bolts of composition. In this case Shingai was the star, improvising melodies and lyrics as if she was having the stuff fed directly into an earpiece. And she was spot on when Chambers added a slightly bland and middle-of-the-road bridge, pointing out that for an anthem to work the audience need to be coaxed into singing by the lyric and then allowed to sing by a melody that doesn't stretch anything but their lung power. There were some neat excursions into musicology too, including a dissection of "Go West" that pointed out its similarity to Pachelbel's Canon,and some wise advice for the budding songwriter.

"The foreplay can't be tedious," someone said, about the bit of the song that tickles you into knowing a belting chorus is coming. The resulting song sounded a lot better in the studio than it did when they sang it in front of a live audience, but a lot of people were moving their lips during the refrain, so I guess it was a success.

t.sutcliffe@independent.co.uk