Photographs instantly transport us to a different place and time. Do you have a shoebox full of your grandparents’ old wartime photos? Don’t know when or where they were taken? We don’t always need a note on the reverse side to tell us.
Photos often reveal clues of not only their date and location, but evidence leading to the subject’s age, rank, unit and function, larger organization, context and military mission. We can figure this out by combining the physical evidence in the image with our knowledge of uniforms, insignia, evidence in military service records, and information in unit histories.
Consider the photo above of a U.S. Army officer. It could have been taken practically anywhere, anytime, and the exact context is anyone’s guess. How old is it? How old is he? Look closely. He practically shouts out the answers to all that and more.
STEP 1: TAKE WHAT THE PHOTO GIVES US.
Starting from the top and working down, we see the officer is wearing:
- a particular style of Army cap bearing insignia on its front-left side;
- a unit insignia patch upon his left shoulder;
- three chevrons on his lower-left sleeve.
STEP 2: CHECK UNIFORM, RANK, AND INSIGNIA GUIDES.
The cap is the U.S. Army’s overseas service cap for officers and enlisted.
The single bar on the cap and epaulets are officer’s rank insignia for lieutenant (enlisted wore round discs with unit designations). In black & white, it’s impossible to say whether the bars are silver or gold to signify First or Second Lieutenant.
The shoulder patch reveals just enough detail to determine Second Infantry Division, or one of the division’s smaller components. You can see several points of a large white star, and at its center is a small portion of the signature Indian warrior’s head – universal elements of this famous division’s widely recognized shoulder insignia still in use today. Unfortunately, the angle in this photo obscures the telltale perimeter shape that signifies his regiment, nor in black & white can we tell the color behind the star to identify his battalion or company.
The three chevrons are World War overseas service chevrons, each signifying six complete months of foreign service, thus proving this lieutenant had served at least 18 months as of the time this photo was taken.
So far, we have determined the subject is a U.S. Army officer with rank of lieutenant; he was attached to the Second Infantry Division; and, by the time this photo was taken, he had performed at least 18 months of World War service overseas.
But, keep going, there’s more…
STEP 3: CHECK MILITARY SERVICE RECORDS.
Calibrate time, place and other more precise details by comparing evidence identified in the photo to relevant textual records in the lieutenant’s Official Military Personnel File (OMPF) and other records.
The lieutenant’s discharge shows he departed the U.S. for service in France on 18 Oct 1917, returning 4 Aug 1919. The departure date — together with the three service chevrons and overseas cap — proves this photo was taken abroad on or after 18 Apr 1919. And, no later than 4 Aug 1919.
A promotion record  shows that earlier, on 27 Oct 1918, this officer was promoted to First Lieutenant, proving his precise rank after 18 Apr 1919 was First Lieutenant, and the rank insignia bars in this image were actually silver in color.
The shoulder patch is too obscured to determine the officer’s regiment. Instead, having established 18 Apr 1919 as the earliest possible date helps us do that. Special Orders in his OMPF show that on 10 Jun 1918, the lieutenant transferred from the First Division to the 23rd Infantry, Second Division. Other records show he remained on duty with the regiment for extended federal service through Oct 1920.  Therefore, at the time of this photo, the lieutenant was, in fact, on duty with the 23rd Infantry Regiment.
STEP 4: CHECK MILITARY UNIT RECORDS & PERSONAL JOURNALS.
The Journal of Operations, 3rd Infantry Brigade, shows that on 18 Apr 1919 the 23rd Infantry was stationed at Vallendar, Germany for occupation duty.  Upon conclusion of occupation duty, the regiment removed to Brest, France, embarking for the United States on 23 Jul 1919. Therefore, this photo was very likely taken on or before 23 Jul 1919.
The officer’s personal military journal shows that between 19 Apr – 23 Jul 1919 he was attached to the Supply Company, 23rd Infantry, Second Division,  proving his functional unit attachment. This also means the specific shape and color of shoulder patch in this photo is round (23rd Regiment) and green (Supply Company).
Finally, from the birthdate of 20 Jan 1890 recorded in his discharge document, we can calculate the lieutenant’s age as about 29 1/2 years. 
We can reasonably conclude this image is about 96 years old and depicts a First Lieutenant, U.S. Army, age about 29 ½ years. The photo was taken sometime between 18 Apr – 23 Jul 1919, inclusive, while he was attached to the Supply Company, 23rd Infantry, Second Division. At that time, he was most likely stationed in Vallendar, Germany, for occupation duty; or, possibly in Brest, France awaiting embarkation to the United States during the regiment’s few remaining days in Europe.
Bringing together all the evidence helps us acquire new and more meaningful insight about the facts and context of this officer’s life in the military as of the time of this photograph.
You may already have the answers to the mysteries about your photos, too!
 Original black & white photograph, privately held, in the possession of [name withheld for privacy], 2015.
 During World War I, the Second Infantry Division developed an innovative shoulder patch system to not only identify division affiliation, but simultaneously identify the smaller unit. The division’s universal white star-Indian-head device were superimposed on various patch shapes which signified the specific regiment. In addition, the shapes were of various colors to further signify the nominal battalion or functional company.
 Military Record and Report of Separation, Certificate of Service, AGO Form WD-98, [name withheld for privacy], Regular Army; Official Military Personnel File (OMPF), Army, Officers, discharge dates of 1917-1952; National Personnel Records Center (NPRC), Military Records, St. Louis, MO.
 AGO Promotion Record, dated 27 Oct 1918, OMPF, NPRC, per endnote #3.
 Special Orders No. 160, Headquarters First Division, A.E. F., dated 10 Jun 1918, and, Special Orders No. 153, Headquarters Second Division, A.E.F., dated 18 Jun 1918; RG 120.9.3 Records of the Combat Divisions, RG 120 Records of the American Expeditionary Forces (World War I); National Archives II, College Park, MD.
 Mayfield, C.O., Captain, Infantry, ed., Records of the Second Division (Regular), 9 vols. (Washington, D.C.: Second Division Historical Section, Army War College, 1929), 6 : n.p.; Northern Region Library Facility, University of California, Richmond, CA; Journal of Operations, Third Brigade.
 “Journal of Dates and Duty Assignments.” Copy of typescript. Privately held by [name withheld for privacy], 2015.
 Military Record of Report of Separation, per endnote #3.