Past the portraits of our nation’s presidents and the Martin Luther King, Jr. exhibit at the National Portrait Gallery, you’ll find a narrow hallway filled with Technicolor images of Roy Rogers and Lucille Ball.

“In Vibrant Color” features 24 of photographer Harry Warnecke’s (1900-1984) unique color photos of celebrities from the thirties and forties who may have been forgotten — or never known — by this generation.

Warnecke, who produced the color images for the “New York Daily News,” used an uncommon technique to produce photographs with rich color. He exposed three different black-and-white negatives through colored filters and then combinef the three images afterwards.

The prints are created using a pigment-based process that makes the colors unusually bright decades later, curator Ann Shumard said.

“The photographic process yields the most amazingly rich and saturated color,” Shumard said. “It is really astonishing when you realize that the color is just as bright as if it were taken yesterday.”

The prints are divided into sections based on the celebrities’ occupations, whether they’re musicians, politicians, actors, comedians or athletes. The exhibit includes pictures of baseball player Jackie Robinson, former president Dwight Eisenhower and comedian W.C. Fields, among a dozen or so others. The photos come from a variety of places, including an 1992 auction and a 12-photo gift from Elsie, Warnecke’s widow.

The exhibit is shown in one hallway, with pictures on both sides. On either side of the corridor, the prints hang on a pale gray wall that makes the vivid colors seem even brighter.

Warnecke was unique in his time for using the rare tricolor print process while most photos were in black and white, but when he died in 1984, much of his work was forgotten. The National Portrait Gallery exhibit is a tribute not only to the past generation’s celebrities but also to the great work that Warnecke did.

“These photos are a wonderful window in an era,” Shumard said. “People were used to seeing everything in black and white. Their movies, newspapers and pictures were all in black and white and to see something in color must have been really amazing.”