Here's a higher res version of the Camp Morton photo. This was one of a collection of four photographs of Camp Morton owned by Eugene F. Drake, a private in Co. I, 60th Massachusetts Infantry. His regiment served as guards at Camp Morton in August 1864 until mustered out on November 30, 1864, so that may give some indication as to when this image was taken.
https://www.loc.gov/item/2012647767/
More on Eugene F. Drake collection here:
http://www.indianahistory.org/our-c...e-f-drake-camp-morton-photographs-ca-1864.pdf
View attachment 133169
Most of Camp Morton's prisoners were from the Western theater - the Army of Tennessee, Morgan's raiders - as well as some from the Trans-Mississippi. Some of the Confederate troops captured in the battle of Helena, Ark., were sent Morton. The 43rd Indiana Infantry had participated in the capture of the 37th Arkansas Infantry at Helena in July 1863 and later met them again while guards at Camp Morton in summer of 1864.
View attachment 133173
Some of the prisoners appear be wearing lighter colored uniforms, quite possibly undyed wool.
View attachment 133159
View attachment 133164