One of the unknown soldiers at the Library of Congress’ extraordinary portrait exhibit of about 400 Union and Confederate soldiers has emerged from obscurity. Many of the men, women and children memorialized in the ambrotype and tintype photographs, are nameless. The identifications were never with the portraits or lost long ago and finding the correct name is unlikely now.

Pvt. Horace H. Smith, Company G, 16th Wisconsin Infantry, was identified thanks to the intense curiosity of a visitor, Dana Shoaf who edits Civil War Times Magazine. Shoaf has a great interest in Civil War uniforms, equipment and photography. He noticed something odd about the uniform and the sling holding a cartridge box of one soldier. He enlarged the image on a library viewer to study it. That is when he discovered what looked like initials on the box.

Shoaf said he kept thinking about the initials and back at the office he and photography researcher Sarah Mock brought up the soldier’s image again on a computer, greatly enlarging it this time. They discovered the solider had state insignia buttons rather than Union and he had substituted a gun sling to hold the cartridge box instead of the regular issue.

It was on the box that the initials could be seen. They looked closer. There was a last name.

“It said H. H. Smith,” Shoaf said. “We could all see it. We all agreed. It was kind of fun.”

Shoaf checked on Smith’s pension file at the National Archives and came up with his full name plus a record of his injuries that led to his discharge in March, 1863. He received a pension of $8 a month at first that eventually increased to $30, he said.

The library’s curator of photography, Carol Johnson, confirmed Shoaf’s research and changed the unknown label on Smith’s portrait.

“This one is most solid,” Johnson said in an email. “It’s not easy to get a name attached to the pic [in this collection].

The exhibit, named “The Last Full Measure: Civil War Photographs from the Liljenquist Family Collection,” closes Aug. 13.