Digital versus contact print comparison

[paulr]

Debating the theoretical maximum resolution of the eye is really just a distraction, though. What counts more is the research done on subjective image quality, which tell us that the 1 to 5 lp/mm frequency range (at ten inches) is what our brains use to discern sharpness and detail. It's the mdulation (contrast level) in this range, rather than the presense of barely perceptible detail in a higher range, that makes a print look sharp or not.

My personal playing around with this suggests that this is a lot of what makes a contact print look like a contact print. An enlargement from a sharp neg with great optics can have impressive modulation at 5 lp/mm, but not nearly as much as a contact print. A look at the MTF charts of the best apo enlarging lenses shows why this is. The lenses are great, but not perfect. They lose several percent modulation even at low frequencies. And if you're making all but the smallest enlargements, you're going to be enalrging detail into that 1-5 lp/mm range that is at much higher frequencies on the negative, and which therefore was imaged at lower modulations.

[bglick]

> It's the mdulation (contrast level) in this range, rather than the presense of barely perceptible detail in a higher range, that makes a print look sharp or not.

paulr, the first time I read this several weeks back, it did not register completly, then when I just re read this line, I am starting to appreciate the value of this contribution. It makes sense, this factor just might be the most signficant issue to perceived sharpness of a print.... superceding the benefits of added resolution in the 10 lp/mm + range.....

now, that being said, I think it would make sense, if one took an image, added contrast and sharpened it digitaly, they printed to either the CSI film recorder at 40 lp/mm using paper, or simply printed a large back lit, then photographed with 8x10 camera using positive paper as the film, this would be a very powerful combination..... assuming the sharpening and contrast improvements overcome the lens loss of the second generation, there is good chance this method may match, or even slightly supercede a contact print. This is why I think many people make 8x10 digital prints that appear sharper than any contact print they have seen.... this is a simple case of the digital manipulation adding more to the image, vs. any of the losses the image experiences getting through to print, regardless of the method. And based on how poweful digital manipulation is, I can see this as being a breakthrough in the contact print arena. Except for purist who are more concerned with the process vs. the final product.

I am curious as to your thoughts on this......