Photographic Essays
Photographic essays were an essential part of the design process for postage stamps. They were small, relatively cheap to produce and easy to mail to interested parties such as design approvers, printers, engravers, regulatory bodies, etc. A photographic essay might occur late in the design process, typically after hand-drawings or other designs were approved. In some cases a photograph of the subject (monument, building, landscape, etc.) might be used as the basis of the photographic essay – see the 1956 photographic essay below with the Leyte Landing Monument on it.
With the emergence of email, digital photography and desktop publishing applications, photographic essays are less common nowadays. It must also be noted that there is often a blurred line between what constitutes a photographic essay and what constitutes a photographic proof. In essence, an essay would be utilized in the design process whereas a proof would resemble the actual finished product (there are no more changes/tweaks to be made as the design is signed off and final).
As you look through the photographic essays below and their corresponding printed stamps see if you can spot any design changes that occurred between the photo and the actual printed stamp (some are more obvious than others).
Essays can be hard to come by as many countries destroyed essays or they remained in the private collections of commissioned stamp designers. I find photographic essays to to be an interesting branch to my philatelic collection.