The economics of filters
We reflect on certain items that are getting more expensive.
It was said, back in the days of film photography, that a black-and-white photographer had to know more about color than a color photographer did. This seeming contradiction came about because an important way for the monochrome photographer to control the appearance of his or her work was through the use of color filters. By the judicious use of filters he or she could control the tonality of each subject based on its color. The appearance of a black-and-white print could vary greatly, depending on this sort of manipulation, while it was a truism that the color in color pictures was either right or wrong. (There were actually some subtle techniques for modifying color photographs, but they tended to be difficult and confined to the more advanced workers.)
Probably the easiest example is a landscape picture involving a blue sky, perhaps with a few clouds for interest. Most black-and-white film is more sensitive than the eye is to blue, and would show the sky very bright. In any case, it would not be able to distinguish the sky from (say) the trees by color. So commonly a photographer would use a yellow filter, which blocks blue light, and the sky would darken, giving something closer to what the eye would see. A green filter would brighten up the vegetation. A red filter would give a dramatically dark sky (sometimes unpleasantly so). In a similar way, a portrait photographer could use a red filter to de-emphasize blemishes. These are obvious effects; more subtle manipulations were of course possible, especially once the photographer had become accustomed to the response of different film emulsions.
To support color-control in black-and-white photography, Kodak manufactured the Wratten standard series of filters. Perhaps the best seller was the yellow #12; many outside photographers kept one on their cameras permanently. Its complement was the 47B, blue. Green 58 and red 25 completed the primary-color set, while there were others that were more expensive and harder to find. It was common, though, to be able to walk into a camera store and pick up a set of three-inch-square gelatin filters (which could be used on any camera) for, say, $20 each.
Our photographer routinely uses his 47B, 58 and 25 for synthesized color pictures. (A recent example is shown above.) His are still in good shape, but recently he checked one of the major online photographic retailers just in case he had to replace them. He was shocked by the cost, which has increased by five to ten times over the past twenty years; some are only available with a wait of several weeks, or in quantities of five or more. He’s not sure he could afford to start his project over. What happened?
We think it’s the reverse of what we described in telescope economics. There, a market for precision optical instruments became large enough for their manufacture to benefit from economies of scale; prices dropped and availability grew. In this case, it’s a result of the fact that few photographers bother with color filters nowadays. The image coming out of your digital camera is already in the form of red, blue and green channels, which can be manipulated in software to do everything our standard set of physical filters could do. What used to be in common use is now of interest only to a niche market, so prices have risen and availability dropped.
Our photographer, however, wants the flexibility of choosing his own colors. He is making up an inventory of all his filters just in case there are some he needs to replace while it’s still possible.
