Gradient background in museums

This is a beautiful depiction of Jesus made from silver in a museum above St. Tryphon's Church in Kotor, Montenegro.  It was suspended against a background of unattractive yellowish fabric on the wall, and I had to photograph through a glass case to get the shot.  I selected the artwork in Photoshop using the quick selection tool, and then I applied a gradient of color, from black to middle gray, using the gradient filter in Photoshop.  Solid black or a gradient consisting of non-distracting and complementary colors makes photographs of artwork more successful that settling for the original background.  This is an HDR image taken from a tripod (this is only one of two museums in the world that Ive encountered that allow tripods).