Royal Collection uses infrared to prove Canaletto did not trace his drawings

The results, say the Royal Collection, give "extraordinary insight into Canaletto's artistic practices".

In particular, they identify the extensive underdrawing of buildings, down to chimneys, windows and facades, and how the artist used a ruler to outline reflections in the water.

Experts can now see how he copied over the pencil lines in ink, before adding spontaneity with freehand birds, clouds and ripples on the water.

A spokesman for the Royal Collection Trust explained: "Canaletto is long thought to have used a camera obscura to achieve topographical accuracy in his work.

"A precursor of the modern camera, the device enabled artists to trace an inverted image of a view formed by rays of light passing through a small hole in a box."

Source: Royal Collection uses infrared to prove Canaletto did not trace his drawings