The Colossus is one such painting in danger of being stripped of its attribution to Goya. Experts have proposed replacing authorship with an attribution to Asensio Juliá, who was one of Goya’s main assistants near the end of the artist’s life. To publicly question the attribution of what is considered one of Goya’s great works was not made lightly, but rather the decision to propose the work to Goya’s assistant Asensio Juliá was made after a lengthy study of the painting during which experts were able to identify several discrepancies both visually and below the surface of the painting. X-ray tests revealed what experts interpreted as the faded partial initials “A. J.” on the bottom left corner of the canvas. Some Goya experts reject the new attribution and maintain that the newly discovered “initials” are, in fact, the first digits of an inventory number. The number 176 is visible in old photographs of the painting. Alternatively, the “initials” have been interpreted previously as the number 18 which alludes to the description of the painting entitled A Giant in the inventory of 1812 that says, "a giant with the number eighteen.”

Self-Portrait, Degas, 1855

The Colossus (El Coloso) (1808–1812), Museo Del Prado, Madrid, Spain

Ultimately, it is a combination of connoisseurship and technical analysis that creates the foundation for the arguments both for and against an attribution to Goya. Goya experts in favor of the reattribution of The Colossus also point to the quality of the work as being slightly inferior to other securely autographed Goyas. Questions about the attribution of this painting arose during the restoration process when experts noticed a disparity in the quality of materials used to execute The Colossus. Other published scholars have subsequently pointed out how the Prado Museum’s technical analysis points to an attribution in favor of autograph Goya by favorably comparing the composition of the painting and artistic techniques with those known to be used by Goya, particularly in Goya’s other Black Paintings. Despite the delisting of the work being made public, experts maintain that corroboration between The Colossus and other works by Juliá must be made before the reattribution can be considered perfectly secure.

Self-Portrait, Degas, 1855

The Milkmaid Of Bordeaux (1825–1827), Museo Del Prado, Madrid, Spain

The subject of The Milkmaid of Bordeaux is often said to be Rosario Weiss, who is said to be Goya’s daughter. An alternative subject would be Leocadia Zorilla de Weiss, who was a nursemaid to Goya in the final years of his life, as well as his lover (and mother to Rosario Weiss). Some scholars have suggested that The Milkmaid of Bordeaux appears aesthetically to be the work of a female and may have actually been painted by Rosario Weiss with the help of the master Goya. X-ray tests revealed sketches of other figures beneath the painted surface, an element uncommon for Goya. According to Prado museum officials, both The Colossus and The Milkmaid of Bordeaux have been under quiet suspicion of authenticity for years.

One of the goals of the exhibition Goya: Avant-Garde Genius, the Master and His School, is to propose a new approach to studying and attributing Goya’s works, with emphasis on the particularity of his artistic process (from drawing to painting) and his autograph works. The project of closely examining the work of Goya and his workshop (particularly, Agustin Esteve and Asensio Juliá), and outside Goya copyists like Leonardo Alenze, could potentially lend new definition to Goya’s masterpieces versus the contributions of his workshop through documentation and technical analysis. Reports state that definitive attributions and re-categorizations will not be finalized until a thorough battery of scientific tests are completed on the Prado’s collection.