Posted By:
Rob DewolfI've worked in Sports departments at newspapers as a writer and copy editor since the days when we actually would walk to a room where where old photos were stored and physcially pull the ones we wanted to use in the next day's paper (as opposed to now, when we typically pull them electronically from a data base).
My guess is that the "106%" marking refers to when the size of the photo was enlarged by that percent for use in the paper (as opposed to your photo having been enlarged to 106 percent). Ditto with the references to picas; at some point someone wanted the photo -- or some part of it that was cropped -- to run in the paper 19x10 picas in size.
I've seen 80-year-old photos that have been reused multiple times in print with 10 different sizes and dates written on the back. Typically an editor or layout person would get the photo from a file, write on the back what size he needed it for the next day's paper (and if needed use a grease pencil to crop what part of the photo he wanted printed in the paper) and then drop it off to the photo department. When the photo department was done, the photo would be returned to its file (in a perfect world, at least). The photo could then be used again in the same way.
So on photos that orginally were used by a newspaper, I'd urge caution in relying on markings regarding size and date on the reverse to determine too much; often these writings had more to do with the photo's use in print rather than the photo itself.
Hope this helps.
Rob