In general, any and all subdivisions appropriate for an image or group of images are used. Chronological subdivisions may be eliminated, however, from certain types of subject heading strings that commonly include specific dates, such as headings for wars and other events, in order to avoid redundancy and potential confusion. P&P catalogers supply nationality and geographic subdivisions depending upon what is known from caption information--research is not usually conducted to discover this information. Subdivisions for both nationality and country are used, even when they refer to the same nation, because each conveys a different type of information (national affiliation in the one case, place of depiction in the other). Moreover, despite the apparent redundancy, using each type of subdivision consistently leads to greater predictability in retrieval.
The order of elements in the subject heading string is: [term]--[topical subdivision]--[nationality]--[country or state]--[city]--[chronological subdivision]. Elements not accounted for are simply left out.
Arms & armament--Italian--Italy--1910-1920 International economic assistance--American--Greece--1940-1950 Women--Employment--New York (State)--Albany--1920
(See instructions in the appendices for further information on usage.)