Digital Photo Printing

It's all in the details !

Consider the obvious viewing extremes:
  • If you look at a digital print with a loupe magnifier you can distinguish the printer dots.
  • If you look at the same print at a distance, you may not be able to distinguish individual pixels so you could have printed it larger.
At some viewing distance:
  • Individual pixels will be just recognizable as pixels and ...
  • The color of every pixel will be a precise as the eye can distinguish -- within the color gamut limits of the printer, of course.
Finding a reference viewing distance:
  • The "Golden Ratio", 1.618, appears often in literature related to artwork which makes it an ideal candidate for photography.
  • 1.618 represents an esthetically pleasing dimentional ratio between two related distances found in nature. [(a+b)/a = a/b]. The 40D sensor, having the same aspect ratio as 35mm film, would be close; (3888+2592)/3888 = 1.666 and 3888/2592 = 1.500. However, the importance atributed to this ratio may be of more usefulness than the value itself since the exact ratios in nature are generally only close to this value.
  • For photographic prints of 3:2 aspect ratio, like 35mm film, a 13x19 print has an area of 247 sq-in; equivalent to a square of 15.7 inches on a side with a diagonal of about 22 inches. Using the Golden Ratio of 1.6 for this 13x19 print gives about 25 inches. How convenient!
  • To make things even more convenient, let's just use the actual diagonal of a print (here 13x19 gives about 23 inches) as the viewing distance. So, it is not a surprise to find comments on the internet that the diagonal measure of a print to be the recommended viewing distance.