Original Civil War sixth plate melanotype of a color sergeant James M. Arnold of the 12th Kansas Infantry. Served with the regiment from September 30, 1862 to June 30, 1865. Seated pose and dressed in his infantry frock coat with sergeant stripes worn on the sleeve and crossed US flags indicating color sergeant. Image is housed in a full leather case. National Archives pension card shows that Arnold also served in the 9th Kansas Cavalry and 2nd Battalion Missouri Militia Cavalry.
Second image has been enhanced (brightness) with scanner to show detail on uniform sleeve.
http://bc-digital.org/civilwararkansas/