One of the most beloved paintings in The Frick Collection, Velázquez’s “King Philip IV of Spain,” has returned to view after an absence of several months. The portrait was cleaned and treated for the first time in more than 60 years with astonishing results, according to Colin B. Bailey, The Frick Collection’s associate director and Peter Jay Sharp chief curator.

Technical studies of the painting were done for the first time and involved microscopy, X-radiography, and infrared reflectography. The work was undertaken during the summer and fall of 2009 by Michael Gallagher, Sherman Fairchild conservator in charge of paintings conservation at The Metropolitan Museum of Art.

Bailey said, “The results of this treatment and examination are nothing short of a revelation. Multiple layers of dull and discolored varnish have been removed, making clear for the first time in decades the extraordinary virtuosity and sureness of Velázquez’s technique, and the subtlety and sensitivity of his composition. We now more fully appreciate the turn of the figure’s shoulder, the weight of his costume and the penetration of his gaze. The previous, rather flat appearance of the painted surface also made it impossible to fully appreciate the artist’s peerless use of impasto brushwork. With this cleaning completed, the painting has been brought back to life.”

“King Philip IV of Spain” is currently on view in the Frick’s Oval Room, hanging in the exact spot where viewers first encountered it in 1935, when the museum first opened to the public.

In the coming year, various aspects of the portrait’s execution, the interventions it has experienced over time, and various discoveries made during its recent treatment will be the subject of a focus exhibition at the Frick.

The Frick Collection is at 1 East 70th Street. For more information, www.frick.org or 212-288-0700.