I am trying to date 2 old b&w family photos I found. Both have the number 49 on the back. I've been unable to find any information online.
My guess is that both photos were taken in the late 40's or early 50's. Can anyone tell me what printing code 49 means? Any help would be greatly appreciated!

The back:
Reverse of photograph with handwritten subject and printed '49'

Click for full size

  • \$\begingroup\$ Post a photo of the rear of the print please. Also, state where you are, and where you think the photos may have been printed - even the city. \$\endgroup\$
    – osullic
    Mar 18, 2022 at 15:27
  • \$\begingroup\$ Hello, I am in NY and believe the picture may have been printed in rural Pennsylvania. Where do I post the rear of the photo? Sorry, new to this forum. \$\endgroup\$
    – James
    Mar 18, 2022 at 15:38
  • \$\begingroup\$ Here is the way to post a image/photo: photo.meta.stackexchange.com/a/4798/34947 \$\endgroup\$ Mar 18, 2022 at 15:50

2 Answers 2


When a roll of film arrived at the photofinishing shop, a return envelope was created. Data such as film type and size, size of prints desired and the surface (glossy - matte, simi-glass), number of prints per negative, plus name and address of customer. The bag was stamped using an ink numbering devise.

The number on the bag corresponds to an adhesive label called a twin-check. A twin-check with this same number is applied to the undeveloped roll of film. A duplicate twin check accompanies the roll into the film developing darkroom. In total darkness, the roll of film is unwound, the duplicate twin-check is applied to its tail end. The film is then developed in a processing machine. Next the developed film is taken to a printing room. The film is now printed by projecting an image of each frame onto light sensitive photo paper. As each frame is printed, an inked numbering device called a back-printer, prints an identifying number on the back of each to-be-developed print paper. The number corresponds to the number on the twin check.

After film processing, printing, print developing, film, prints and envelopes arrive at an assembly station. In the envelope goes developed film, prints, and the envelope is priced. This numbering scheme allowed correct assembly of the finished goods. The envelope is now ready for pick-up -- A twin-check - back=printing numbering system similar to the system used in a laundry.


Most likely the code doesn’t mean anything anymore. It was for internal use in the lab where the photo was processed to help return the right pictures to the right customers.

Maybe a former owner of the picture rubber stamped it as a date since it is in the range of possible dates. But that’s just wishful thinking without corroborating evidence.


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