Last time I wrote about improving color image permanence through digital imaging. I wish I could report similar good news for black and white. Our standards are higher for black and white images, since we the standard techniques yield images with prospective lifetimes measured in triple digits. Much of the slower progress for black and white images is due to lack of attention: no matter how much art photographers love monochromatic images, the sad truth is that black and white computer imaging is a technological backwater. Of all the potential consumers of digital image-making equipment, only a tiny fraction care about monochromatic images, so the developers of such devices don’t spend much time worrying about the problem. Almost every successful path to black and white digital images involves using equipment in ways the manufacturer did not intend.
One way to make a black and white print is to send a monochromatic image to a color printer, maybe even get fancy and simulate duotones or tritones. A superficial analysis says this should work; after all, grey is a color, isn’t it? This plan stumbles because the eye is much more sensitive to small color shifts for nearly-neutral colors than it is for highly saturated colors. When the whole image is nearly neutral, the eye is exceedingly critical, so that it’s hard to get the tones to look right, and nearly impossible to have them stay looking right in different lighting and over time.
A variation on this theme is to use a third-party monochromatic ink set in a color printer. The printer manufacturers hate this, because they make all their profits on the ink, and they retaliate by voiding your warranty. Because the market is small, the companies producing monochromatic inks tend to be small as well, and there aren’t the legions of chemists that are developing color inks working on the problem. In addition, with most printers, a piece of software called a printer driver needs to be written, debugged, and supported to make this scheme work. Nevertheless, there are several suppliers of such ink sets. Special ink sets yield prints that have consistent tonality and maintain tonality under different illuminations, but their longevity is open to question.
Other approaches to back and white digital images involve using conventional photographic materials. There are several digital printers designed to expose color photographic paper. When loaded with black and white paper, these printers do a fine job, but they’re priced beyond the reach of individual photographers, and thus work must be sent out. The lack of immediate feedback on subtleties in the output makes this approach problematical for many photographers.
A photographer could obtain a negative of a digital image and print it on conventional photographic material. A small negative could be enlarged onto silver gelatin paper, and a large negative could be contact printed on a wide variety of materials. Producing platinum or gum bichromate prints from digital images provides a delicious resonance between the high-tech present and the romantic past. Getting the negative is the tricky part. Film recorders can produce enlargeable negatives, but the level of quality required to avoid digital artifacts is elusive. Image setters were originally designed to expose photographic film for the creation of offset lithographic printing plates; with proper calibration, the film can be used as a photographic negative. However, the quality required for photographic purposes means that most service bureaus cannot reliably produce acceptable negatives. Either the photographer or the service bureau may decide that the amount of experimentation, setup, and rework required to get acceptable output is too great, especially since the trend in printing is towards direct-to-plate processes that bypass the film entirely.
There’s another path to a printable negative: the very same color desktop printer that can’t produce permanent output on its own. Load the printer with transparent film. Use standard inks, since the color of the ink will have minimal effect on the finished print. The price is right. The feedback is quick. Can you get sufficient density? Can the tones be smooth and repeatable? Will there be visible digital artifacts or annoying defects in the transparent substrate? I will be doing some experimentation over the next few months, and I’ll let you know what I find out.