Deattribution of Rembrandt paintings has been going on among art historians for decades, constantly winnowing a corpus inflated by the 17th- and 18th-century practice of regarding many works simply in Rembrandt's style as "by the master."
Source: wiktionary
Attributions, deattributions, and reattributions are often more easily made after reviewing x-radiographs, infrared reflectograms, dendrochronological data, and pigment analyses.
Source: wiktionary
[I]n the world of art, authors are always dying off. Works that were previously assigned to a known name, works that were among the most famous, find themselves stranded in anonymity. The process is called de-attribution.
Source: wiktionary