A major distinction of APS film was the ability to record information other than the image. This information exchange was most commonly used for print aspect ratio, but could also be used to record the date and time that the photograph was taken, store a caption, and record exposure data such as shutter speed and aperture setting. This information could be read by the photo printing equipment to determine the print aspect ratio, print information on the back (or, rarely, the front) of the photograph, or to improve print quality.