There's something so haunting about Civil War tintype photographs. The faces of the soldiers express hope, fear and a sense of patriotism that is not seen in modern soldier's faces today.
I was so glad to see photographs of black soldiers among the ones in the photoset, they were all wearing Union uniforms. Given that black soldiers were fighting for their right to freedom, and were promised a generous pension upon completion of their duty as soldiers, many fought in the war willingly.
these two were brothers who fought in the same regiment.
The Library of Congress has an extensive collection of these tintype photographs, of which there is a great set available for viewing on Flickr.