An 18-month-long conservation project of a major work by Paulus Potter has revealed the Dutch artist scaled back a part of a bull's anatomy to spare the blushes of his 17th-century audience.
Staff at the Mauritshuis in The Hague removed layers of varnish and paint from previous restorations and also showed how the painter had changed the size and shape of his work before completing it.
Conservator Abbie Vandivere said: "It started as a smaller composition, just a painting of a bull, maybe with the cow in it. When he made the composition bigger, he made a ton of changes, also to parts of the bull’s anatomy… His balls were bigger and lower."
The painting has a tempestuous history - part of the royal collection in the Netherlands it was stolen by French troops and shown in the Louvre in Paris for years before it was returned.
It can be seen in the museum's conservation workshop, which is open to the public, for another month before it is moved back to its Potter Gallery.