The Frenchman who taught Lowry how to paint matchstick men

The work of Adolphe Valette has been little known, until now, says Jonathan Brown

For decades they have hung on the walls of art lovers' homes across northern England, their true value scarcely even guessed at by their owners.

Now sale prices of works by Adolphe Valette, the French Impressionist who taught LS Lowry to draw his celebrated matchstick men and mill worker scenes, have soared nearly a hundred fold.

This month, two new exhibitions marking the artist's talent in capturing the dark beauty of Edwardian Manchester, get underway. Among the items going on show at The Lowry gallery in Salford will be nine paintings and sketches donated by private collectors who answered a public appeal to scour their homes, attics and storerooms for previously unseen work by Valette.

Pieces including a preparatory sketch of a lost work, possibly entitled Les Baigneuses (Bathers) and a large painting Femme L'Avant whose owner said it had not been displayed since 1934, emerged in local homes.

Yet while Lowry has become one of Britain's most bankable artists – his Piccadilly Circus painting belonging to the hotel tycoon Lord Forte is expected to set a new world record of £6m when it is sold at Christie's later this year – the former master has continued to languish in relative obscurity outside Manchester. But the lives and talents of the two men were critically entwined and now the teacher is attracting renewed interest from collectors who also admire the work of his most famous protégé.

Both men arrived at Manchester School of Art in 1905. Lowry then aged 18, was little more than a Sunday painter while Valette brought a whiff of glamour and the exoticism of the painting movement that was set to sweep the world before it. Lowry studied under the Frenchman for a decade – assiduously learning the drawing techniques in his life classes. The descendants of many of the models they painted are also believed to be still living in the North-west.

Valette introduced his pupil to the work of Monet and Degas among others but crucially inspired him to regard the industrial landscape and its people as worthwhile subject matter. "I cannot over-estimate the effect on me of the coming to this drab city of Adolphe Valette, full of French Impressionists, aware of every-thing that was going on in Paris," said Lowry of his former master.

Valette too saw the austere beauty in Manchester's smoggy streets. Among the subjects he chose were tug boat scenes on the Manchester Ship Canal and views of the red brick Victorian architecture often shrouded in fog.

Bill Clark, who is holding the largest ever sale of the artist with 24 of Valette's works on display at his gallery in Hale timed to coincide with The Lowry show, said large canvases depicting urban life in the period can now fetch up to £50,000.

"I am often called in to do valuations where the owner will realise they have a Valette but they don't realise what it is worth," he said. "They are often normal working people who bought them for perhaps £40 in the 1970s – which was quite expensive – but they just loved his work. The uplift in price has been huge over that period," he added.

It is not known why Valette chose to come to Manchester. During his time at the School of Art, before his retirement through ill health, he lived among industrial workers in Gorton. He returned to France and died during the Nazi occupation in 1942. His work returned to Manchester 30 years later when interest began to stir in Lancashire's very own adopted Impressionist. Today the city's art gallery has nine of his paintings on display.