Lasting images
Writing is not the only medium we might want to preserve.
Last week we commented on the longevity of paper in the form of written books. Our photographer reminds us that other things were recorded on paper, in particular images in the form of photographs. It is ironic that a picture capturing one-hundredth of a second of a transient event could be among the longest-lasting documents we can routinely make.
It didn’t start out that way. By the first half of the nineteenth century it was well known (among chemists, at any rate) that silver chloride would darken on exposure to light, and if coated on paper and properly manipulated would form a recognizable image. But to look at the image one had to shine more light on it, which darkened it further, and eventually it would blacken entirely. It was the accomplishment of (chiefly) Fox Talbot and John Herschel to find a way to “fix” the image at a convenient stage, rendering it “permanent.” Well, at least longer-lasting. After the first discoveries there was much chemical tinkering and a lot of working out how important minor contaminants were. At last there was the black-and-white photograph on archival paper, which was made up of minute deposits of silver metal in the paper itself. It would last as long as the paper did, without fading or distortion. We do not yet know how long it can last, for the earliest proper examples show no deterioration so far.
[We should emphasize that the procedures must be followed carefully and thoroughly. Our photographer experimented with a slightly unusual process involving “printing-out paper” some years ago. He was cautioned to use enough chemicals and to wash the print thoroughly, which he thought he did. But all of his POP prints are now quite blank.]
Color photographs are another story. When color film became widely available in the second half of the twentieth century it quickly gained a deserved reputation for fading and shifting colors. (Properly-handled Kodachrome was the exception.) In time the dyes were stabilized and made more durable, more resistant to light and other environmental factors, so that for most purposes they’re quite acceptable now. But they are still in principle more vulnerable to time than black-and-white.
[Our photographer would like to experiment with an autochrome, an early process for color photography. The results have a particularly lovely soft quality. But he’s never actually seen one. The dyes involved fade if exposed to light for an extended period, so they are rarely displayed. In fact all he’s seen are book reproductions of standard color pictures of autochromes. Alas.]
Well, photographs are digital now. Initially they were even more transient than chemical images, because there were many formats stored on constantly changing computer operating systems. If you didn’t actively migrate from format to format and from system to system as the old ones became obsolete, in a few years you wouldn’t be able to look at your old pictures at all. And, indeed, you might not really care to; the quality of a sub-megapixel file from a noisy sensor may not be very attractive nowadays.
The pace of format/system change seems to have slackened and the quality of digital photographs has increased beyond description. But you still have to decide to move your files when your machine or system becomes obsolete. In choosing which pictures to save, you are performing the same function as the monks of the Middle Ages deciding which manuscripts to copy. The key to photographic immortality is the same as for literary immortality: produce something worth copying.
