Photographing documents/official records Lincoln White House

[Anita]

According to "The Rail Splitter", before donating his original final draft of the Emancipation Proclamation to the Chicago Sanitary Commission to help them raise funds, he made photographic copies of it.

"Lincoln wrote to the ladies in charge of the fair on October 26: “According to the request made in your behalf, the original draft of the Emancipation proclamation is herewith enclosed. The formal words at the top, and the conclusion, except the signature, you perceive are not in my handwriting. They were written at the State Department by whom I know not. The printed part was cut from a copy of the preliminary proclamation, and pasted on merely to save writing. I had some desire to retain the paper; but if it shall contribute to the relief or comfort of the soldiers that will be better.” This document, principally in Lincoln’s handwriting, was the final draft of the final version. Lincoln had photographic copies made prior to relinquishing his Proclamation of Freedom.

"Thomas B. Bryan, Chicago lawyer, businessman and Lincoln supporter paid $3,000 for the document (destroyed in the October 1871 Chicago fire), and donated it to the Chicago Soldiers’ Home."
http://railsplitter.com/?page_id=242 (interesting article about Lincoln's gifts to and from the Sanitary Fairs.)

I was not aware that photography was used to make copies of documents/records during the Civil War.
Has anyone seen such a photograph? Any information much appreciated. Anita