Cannonballs: 1862

I've been trying for a while to find any information on the resolution of collodion glass plates. Unfortunately with little or no result.

Now I've got even more confused: Is the Civil War picture above really a half of a stereoscopic camera? If so, it's original size "should be" 3x3 inches, as far as I know.

If the original size of the picture is 9x9 inches, as you write, how can it be a half of a stereo camera?

[The stereograph is two 9x9 plates taken with the same camera, which is moved a few inches for the second exposure. (Incidentally, 3x3 would be one-quarter the size of a 9x9 plate.) - Dave]

Those are mortar shells, primarily anti personnel use, not for breaching fortifications. Very high trajectory angle, short range. The fusing holes you see in the picture are somewhere between 5/8"-3/4" diameter to give some perspective of "caliber."

What caliber are those ?? They look HUGE !

I'm not sure what you mean by computer-enhanced. It's been digitally processed (scanned, inverted, adjusted for contrast, resampled to fit the average video screen), obviously, or else you wouldn't be looking at it on your computer. It's sharp because it's big media, a glass-plate negative 9 inches by 9 inches ... you can get an incredible amount of detail in 81 square inches. The history of photography has generally been from high information density ("sharp") to less over the years as the size of cameras (and consequently recording media) has decreased. Just about the sharpest photograph you'll ever see is an old daguerreotype if it's in good condition. If you make the conservative estimate that the emulsion on a glass collodion plate can register 1000 dpi of detail, this 9x9 is the equivalent of an image taken by a digital camera with an 80mb sensor.

I can't believe how crystal clear this picture is from 1862-63, has any restoration been done to it, or was it computer enhanced from the original?