NEW YORK CITY — “There’s just a feel of greater depth and mystery about the picture under gaslight,” said Charlotte Hale, conservator in the department of paintings conservation at the Metropolitan Museum of Art. In an effort to better understand Georges Seurat’s painting “Circus Sideshow (Parade de cirque),” on view through May 29, the conservator used digital editing to simulate what the painting would like like when viewed away from bright gallery lights and under the flickering gaslights found in a number of the artist’s works in his imagery of nighttime entertainment scenes. For more information, www.metmuseum.org.