Monday, May 14, 2007

Black and white revisited

Images not readded.

Ok, a towel is a towel is a towel, but not really. Huh? This photo was an exercise in white, but it got me into rethinking black and white images as I was scanning the roll of black and white negative film (Agfapan 400). I talked about one view I have about black and white images. This is a followup on that view but more about film versus digital.

There are arguments here? Oh, yeah, it's the film versus digital debate, and the digitized film versus digital debate. It's about those pesky bits computer use, which require 16-bits numbers. Digital cameras are 12-bit images and convert the 12-bits into a 16-bit number the computers can handle. It's not a 12-to-16 conversion but a 12-bit value converted to a 16-bit value. Sorta' a pseudo 16-bit number.

But when you scan a film image you have a choice of 8-bit or 16-bit images. Since most applications use 8-bits, only higher end printing and publications use 16-bit images, sometimes you can scan and work with 8-bit images with little discernable loss in the final images. Some argue against this, and most of their points are correct for some images and applications. You do lose some color range, but it doesn't hurt in many images for size and color.

The key here is that you can scan at a true 16-bit range, so instead of getting only 4,096 values with 12 bits, you get 65,536 values, or a 16 times greater range, whether it's color or grayscale. That's a bunch of bits, a lot of gray in the grayscale or color between colors. And that's the argument for digitized film images.

And this makes film better? Not really because to balance that argument you have to account for the resolution of the film versus the digital capture. In general, about 8 megapixel sensor is comparable to most 100 ASA films, most being consumer or prosumer film where some professional films have a higher resolution (grain) and would require higher sensors to match the resolution.

Where this issue is often debated is when digital images are "improved" from their original resolution using the tools most photo editing software packages have. This was demonstrated recently with the New York Times produces some 11x14 prints from consumer digital cameras, professional digital cameras and film cameras. They showed the final prints had very little difference.

The difference, however, was in the original image from the camera (digital or film). The film and professional digital camera had several times more detail in the original, and required less work to make it a good print. The consumer camera's image made up for the detail in the photo editor creating the detail from the existing information. In short, it was less real, but not that you could tell.

But back to the argument of this essay, I just wanted to note there's other arguments in the film versus digital debate, and this is one I thought was interesting. A towel isn't always just a towel. It depends on how it's recorded and processed.

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