Now that you've seem some images compared directly, my rambling conclusions might make some sense. I'm sure there are technicalities and issues I have missed, but this little experiment has pretty much confirmed for me what I have intuited for quite a while ...
What Exactly Are We Seeing Here?
In a word: depth. A third dimension.
Although it can if handled properly, film doesn’t always offer the apparent “razor sharpness” that seems to have become a prized characteristic in digital images. But we have to keep in mind the fact that “sharpness” is not the same thing as “detail.” The latter, in my opinion, is far more important. And the shapes of those details are essential to defining them in the three dimensions that they occupy.
In a digital image, the smaller the details become, the less form can be represented within them. The fine tonal gradations that make, for example, the links in a chain many meters away appear to have volume are essential both to giving the chain itself depth and form, and to relating the chain to its surrounding environment. Of course, ultimately, all of this takes place within the confines of our own craniums, but that’s the way we see the real world as well as the way we interpret two-dimensional representations thereof.
Film, despite its grain and fuzzy little clouds of dye, seems to be better at reproducing gradations within the tiniest details that add up to give a photographic image an overall impression of depth and dimensionality. This is particularly true in the medium and large film formats. It can be subtle – something that is more "felt" (i.e. perceived subliminally) than in-your-face obvious – but I believe the preceding examples support that theory.
But they're Scanned Images, and Therefore Digital!
Indeed they are. And that is one of the arguments often trotted out in an effort put those who dare say they can see a difference in their place. But I think the answer is quite simple: resolution. I can scan film images at up to 6400 spi (samples per inch) on my Epson flatbed, but thus far I've found that scan resolution that high is really only necessary for 35-mm film. I scanned the 6x9 image used for this test at 4800 spi, which gives me an enormous file that is more than 15,000 x 10,000 pixels ... way too big for most practical purposes. Photoshop isn't exactly snappy with files that large either. For most practical purposes medium-format film can be scanned at even lower resolution with perfectly acceptable results.
RAW files from my 12 megapixel Nikon D700 or 10 megapixel Leica M8 don't even come close to the theoretical resolution available from a good scan. The italics in that last sentence were intentional, because the theoretical resolution of an optical scanner is almost never fully realized, but the output I'm seeing with my own two eyes indicates that, from medium format film, it can be significantly better than what is available from the average current prosumer or even pro DSLR sensor.
So ... What About a 45 Megapixel Digital Back?
I honestly have no idea. Companies buy those things, not people. OK ... maybe that was sour grapes ... In reality I'm pretty sure that when affordable digital capture in the range of 150 megapixels becomes available I might have to look for other reasons to justify my campaign for film. But the reality at the current time is this: we're not there yet.
Don't Get Me Wrong: Digital is Good
Before anyone gets the idea that I'm ready to give up digital entirely and go live in a cave somewhere: I really do like digital photography, and use it for a large percentage of my image-making tasks. What I'm trying to convey in this article is that film still has many advantages for quality image making – including the more practical considerations mentioned on the next page – and that anyone wanting to create images that really sing would be missing out by not exploring the options provided by film as well as digital.
Digital for Color, Film for Black & White ... or so I thought
This is a mantra I have repeated many times myself, and something I believed until I actually did the side-by-side comparisons presented here. I will admit that I actually do believe that digital imaging in its current form just doesn't have what it takes to make great black and white images. This may be in part due my familiarity with the look of the medium, but it seems to apply to many others as well, as evidenced by the multitude of techniques and software tools that have become available to convert digital images to "film-like B&W." Thus far I have found that if I want the look of black and white film, shooting black and white film is the easiest and surest way to achieve it.
For color, on the other hand, digital cameras offer consistently better color accuracy than film, plus the ability to easily fine-tune white balance and other color parameters after the fact. But this comparison has shown that the resolution and micro-gradation issues apply to color images as well, and that properly exposed and processed medium and large format color film still has loads of appeal. So I guess my new mantra will have to be: digital or film for color, film for black and white ... unless you like the way black and white conversions from digital images look ... which I don't.
And What About 35-mm Film?
In general I think the same principles apply, but the smaller film size means that grain becomes much more obvious, so either you limit yourself to relatively small reproductions or take advantage of the grain. My approach would be the latter. 35-mm film has a unique vibe that can lend texture and character to images that digital simulations fail to achieve. That's just my opinion, of course. And it's a fact that the right 35-mm film handled properly can deliver impressive technical results. But for me 35-mm film is akin to painting with a broad brush, while medium and large-format film makes it possible to produce images with absorbing depth and detail.