Long Before Technicolor

ENJOYED “FROM BLACK and White to Technicolor,” by Tom Huntington, in the Summer 2.001 issue. It mentioned James Clerk Maxwell’s extraordinary 1861 demonstration of photographic color reproduction, in which he photographed an object three times through red, green, and blue filters and projected positive transparencies together through the same filters. This experiment should have failed, since sensitizing dyes were not yet invented and thus his film could have been sensitive only to the blue light that silver halide could record. The red—and greenfiltered records should have been blank.

How did he do it? With the help of a series of coincidences. Strong blues and greens were separated because Maxwell’s green filter leaked slightly into the blue region, and since strong greens have some slight reflections in blue, the long exposures he gave the greens allowed that leakage to expose the film. For the red separation, it turns out that Maxwell’s red filter also transmitted ultraviolet, to which the film was sensitive, and synthetic dyes, such as that in the ribbon he was photographing, tend to have secondary reflectances in that spectral range. Maxwell became the father of modern color reproduction through serendipity.

Mitchell Rosen
SENIOR COLOR SCIENTIST
MUNSELL COLOR SCIENCE LABORATORY
ROCHESTER INSTITUTE OF TECHNOLOGY
ROCHESTER, N.Y.

The Power of Priximity

READING DAVID COLLEY’S most interesting article on the proximity fuze (“Deadly Accuracy,” Spring 2001) brought back memories of serving on the USS Richard E. Kraus from 1951 to 1954. The Kraus was assigned to the Atlantic Fleet Operational Development Force mainly as a gunnery experimental platform. By the 1950s it was said that the Kraus had fired more five-inch rounds than any destroyer in all of World War II. Four of the six rifles were so worn they were seldom used except for fuze testing. The operations consisted of firing rounds under every conceivable weather and sea condition at both air and towed targets to see if the devices would pre-detonate, misfire, or function as designed.

Our air targets were radiocontrolled F4-F drones. Because of the volume of our firing, the Kraus became known as “the drone splasher.” On one spectacular day, three drones were downed. What made this so unusual was that the rounds contained dummy charges with only enough explosive to provide a visual marker for photography. Yet the gun crews, firing 18 to 20 rounds per minute, regularly put the rounds so close to the target drones that they damaged them beyond flying capability anyway. A credit not only to the gunners but to the fuzes, doing just what they had been designed to do.

Basil Holcomb
KELSEYVILLE, CALIF.

The Power of Priximity

I WAS A DESTROYER GUNNERY officer from 1942. through 1945, and I suspect that few now living can speak with more authority than I on the value of the proximity fuze. Let me add the following to Mr. Colley’s excellent article: On the lighter side, the questions of what to call ammunition equipped with these secret devices was soon answered by the sailors. Some genius of a gunner’s mate named them “Buck Rogers,” after the futuristic radio hero, and it stuck. In reporting the number of rounds fired in an engagement, each ship radioed the number of “AA Common” and the number of “Buck Rogers.” Unambiguous and, if overheard by the enemy, uncompromising.

The proximity fuze was the key to surviving a suicide attack, and I am certain that I owe my life to that complex device, not once but many times over.

John T. Pigott
LIEUTENANT COMMANDER, USNR (RET.)
SAN GABRIEL, CALIF.