1.  Field of the Invention:
The present invention relates to a photographic printing apparatus, and more particularly, to a photographic printing apparatus for printing on printing paper images carried on a photographic film using a manually corrected exposure value. 
2.  Description of the Related Art:
Photographic printing apparatus are known, in which the images recorded on a photographic film, such as a developed negative, are printed on printing paper and the printed images are then developed so as to provide prints. 
Such photographic printing apparatus fall into two categories, an automatic photographic printing apparatus that is called an automatic printer) in which the exposure value needed for printing on a printing paper the images carried on a film is automatically corrected, i.e., the printing operation is automatically conducted, and a manual photographic printing apparatus (that is called a manual printer) in which the exposure value required to print on a printing paper the images carried on a film is corrected by the operation of an operating portion which is conducted by an operator. 
Automatic photographic printing apparatus are used to conduct in succession a series of processes including the development of a photographic film, printing of the images on that film on a printing paper, the development of the printing paper with the images printed thereon, and the cutting of that printing paper for each frame image. 
On the other hand, manual photographic printing apparatus are employed to provide prints when the prints prepared by the above-described series of printing processes were unsatisfactory or to provide additional prints. 
In the case where printing is conducted by the above-described sequence of processes using an automatic photographic printing apparatus, testing is conducted before printing is started, and printing is then performed with the automatic photographic printing apparatus on the basis of the test results.  More specifically, a semi-circular notch is provided on the side of a photographic film by a notch puncher for each frame image, and data such as frame number data and exposure correction data to be used to correct the exposure value corresponding to the average transmission density (LATD) for the images on the film is recorded by a puncher on a paper tape which serves as a recording medium.  The average transmission density is obtained by the automatic photographic printing apparatus through the actual measurement.  Subsequently, the paper tape is set in the automatic photographic printing apparatus, and the film is conveyed in synchronism with the paper tape so as to detect the notches by a photoelectric switch or the like.  During this operation, each time a notch is detected, the film is stopped at a position where the frame image corresponding to the detected notch is suitably located, and printing is then automatically conducted on the basis of the average transmission density or the exposure correction information recorded on the paper tape.  Thereafter, the printing paper with the images printed thereon is developed by a developing device.  The developed printing paper (prints), together with the paper tape, is set in a printing device.  In this printing device, the exposure correction data and the frame number data recorded on the paper tape are read while the paper tape and the printing paper are being conveyed synchronously, and the data read is printed on the rear surface of the printing paper with the images printed thereon. 
The printing paper on which data has been printed is cut for each frame image.  Since each of the prints has the frame number for identifying the corresponding frame image on the film printed thereon, when printing has to be conducted again due to unsatisfactory printing results or when a customer orders additional prints, the prints can be readily made to correspond to the frame images on the photographic film. 
As stated above, re-printing or additional printing is conducted using the manual photographic printing apparatus (that is called a manual printer), and this manual photographic printing operation involves redetermination of the exposure and manual correction of the exposure value. 
In the manual photographic printing apparatus of the above-described type, the exposure value required for printing the film is corrected by the operation of the operating portion each time printing is conducted, but the obtained exposure correction information or frame number data is not recorded.  Therefore such data cannot be utilized when re-printing is repeated several times due to unsatisfactory printing results or when the obtained prints are collated with the frame images on the photographic film.