Determining and producing an optimum photographic print for photomechanical reproduction

This research has explored the possibility of determining the optimum black and white photographic print characteristics for paper surface, image color, and contrast to achieve optimum reproduction from that original for a given set of printing press conditions utilizing single impression offset lithography. A random population of 101 observers evaluated the reproduction of eighteen different photographic prints of the same subject from the identical film negative. The prints varied in contrast grades from grade one to grade three; in image color from warm black to neutral black to cool black; in surface characteristics from glossy to semi-lustre to matte; and surface finishes of smooth and textured. The reproductions studied were produced after a tone reproduction analysis was conducted to determine the printing press characteristics. To reduce variablity the same press, paper, inks, and plates were used for all the press tests. The film negatives were generated by scanning each of the eighteen original photographic prints on the state-of-the-art Crosfield Magnascan 640 utilizing a predetermined program derived from the initial press and tone reproduction data. The observers were asked to choose what they believed to be the best three reproductions and the three most inferior reproductions. To analyze the characteristics which contributed to the findings of certain reproductions being selected superior to others a correlation analysis was performed. With this information, the paper characteristics which yielded the optimum reproduction was determined. These characteristics are: A medium to double weight paper stock A cool black image color A smooth, glossy surface (not ferrotyped) A contrast grade between 1.5 and 2.5 when the negative has a density range between 0.90 and 1.3 A density range of the original greater than 1.4 but less than 1.9 with gradients equal to 12 plus/minus 1 gradient To obtain the appropriate highlight, midtone and shadow densities on the photographic print, a darkroom tool was developed and successfully tested as a three step reference for the photographer to insure proper placement of these predetermined tones for an optimum reproduction. The visual comparator is waterproof and is used when the print is wet; however, examination of the photographic print takes place under standard viewing conditions. Another advantage of the comparator is that it is made of the same photographic material as the photograph itself. This study shows that a systems approach can be applied to the creation of the photographic print to incorporate photography with the reproduction process producing high quality reproductions