Claude Monet's Haystacks, midday (1890) will be seen in its original state for the first time in many years in the National Gallery of Australia's upcoming exhibition Monet: Impression Sunrise.
Senior conservator David Wise said the painting, one of two Monet works in the gallery's collection, had been on exhibit until last year when it was removed to prepare it for Monet: Impression Sunrise.
The last time it went out on loan was in 2016 for a Monet exhibition in Copenhagen.
The conservators carefully removed layers of dust and varnish over several month so it could be exhibited as the artist intended it to be seen.
"Varnishing is how a picture is treated to make it more shiny," Mr Wise said.
He said someone, at some point in its history, applied varnish before the painting was purchased by the gallery in 1979.
"We know Monet preferred to have a matte finish - we know varnishing wasn't his preference," he said.
The NGA's curator of international painting and sculpture, Simeran Maxwell, worked with Marianne Mathieu of the Musée Marmottan Monet to assemble the exhibition.
Gallery director Nick Mitzevich said the work that gave the exhibition its title, Monet's Impression, Sunrise, was being exhibited in the southern hemisphere for the first time.
It was one of many works on loan from the Musée Marmottan Monet in Paris.
Other sources included the Musée d'Orsay and the art galleries of NSW and South Australia as well as private collections.
Mr Mitzevich said Monet was "the most influential artist of the last 250 years", but that he had his influences too.
As well as career-spanning Monet works, up to the Waterlilies series that occupied his later years, the exhibition will also include works by artists who influenced the impressionist master.
These include British painter J.M.W. Turner, whose works Monet saw at the National Gallery in London, and Eugène Boudin, who encouraged the young Monet to paint outdoors to capture the effects of natural light at different times of day.
Monet: Impression Sunrise will be exhibited at the National Gallery of Australia from June 7 to September 1, 2019. nga.gov.au.