As little as a year or two ago, it was possible to be skeptical about the future of electronic publishing, but it's becoming increasingly clear that Kindles, iPads, and the like will soon be the dominant medium—if, indeed, they aren't already. As a novelist this bothers me not at all; though I prefer paper, I don't care how other people read, so long as they do. But novels and nonfiction aren't the only things that come in book form. Unless you're very dedicated, and very well-traveled, most of the art and photography you've seen has been on the printed page as well. Will these, too, gradually be replaced with e-books? I suspect not, and I certainly hope not, but to understand why, we need to indulge in a little metaphysics.
A book—or, for clarity's sake, let's say a work of literature—is impervious to the constraints of its physical medium. From a literary standpoint at least, every instance of "The Lake Isle of Innisfree" is identical. Whether you read it in a cheap paperback or a first edition, on a computer monitor, an e-reader, or in Yeats' own handwriting, it's the same poem.
Paintings and sculptures, on the other hand, are quite the opposite. They exist only in the form in which they were made, and any reproduction is no better than a paraphrase. Movies and recorded music are somewhere in between; they can be copied, but to better or worse effect depending on the process and the medium.
Photography is somewhere in that same middle, alongside music and movies. The negative, or perhaps the original print, is the actual artwork, but mostly what we see are reproductions and reprints. The difference is that, with the advent of the digital age, the technologies for reproducing movies and music dropped in quality, and then gradually became better, while some crucial aspects of the technology for reproducing pictures grew much worse and stayed that way. And since, for our purposes, all art books—including, say, a catalog of Van Gogh paintings—are essentially books of photographs, this dismal history applies to a great range of publications.
From philosophy to arithmetic: Bear with me while we consider the problem of resolution. Monitors, inkjet printers, and books all make images out of dots, in the first case of projected light, in the second and third of light reflected off of paper. Each method is measured in its own way, and comparisons can be difficult, in part because their perceived quality depends on how far away you're standing, but the numbers are nevertheless revealing. Electronic screens are specified in pixels per inch: Most HDTVs come in somewhere under 60 ppi. PC desktop monitors run around 92 ppi, and Apple's are usually 72 ppi. The iPad is 132 ppi, and the iPhone 4 is, oddly enough, the best of all, with an especially dense 326 ppi—but then, it's a very small screen.
Printer resolution is measured in dots per inch: Most consumer grade inkjets can easily manage 600 dpi. Halftone printing, which is what most newspapers, magazines, and books use, is more complicated, and uses a system based on lines per inch. Newspapers publish photographs at about 85 lpi; a glossy magazine up to 185 lpi, and a well-produced photography book might get as high as 300 lpi—about the same resolution as a 600 dpi print, which is to say, about 8 times finer than an Apple monitor. The result, especially on high-quality paper, is much greater detail and a much subtler range of tones.
Granted, technology has a way of changing very quickly. But computer monitors have stayed pretty much the same for a very long time (and most e-ink devices are, for the time being, monochrome, medium-resolution, and tonally crude). And even in a world in which computer screens are as dense and detailed as well-printed books, looking at photographs on electronic media will be at best misleading, and at worst miserable.