Banner Mania

Photo Rule No 6. Events taking place SIMULTANEOUSLY happen in parallel, even when viewed from different positions in close proximity.

Dark Moon, p. 43

Of all the photo rules that David Percy invented, this one is the silliest. Any alleged photographer who really believed that things look the same from all positions should resign from his photo club with apologies, give his camera to someone who knows how to use it, and perhaps get a dog to lead him around.

So how did Percy come up with such an absurd rule? Apparently because the way the Apollo 16 flag appeared when John Young gave it his "big Navy salute" before the camera and on TV. Here are the two scenes of that event, as reproduced and annotated on page 43 of Dark Moon:

John Young rises for a drooping flag... (Dark Moon, ch. 1 ill. 62)

...and here the flag appears to straighten out. (Dark Moon, ch. 1 ill. 63)

And here's what David Percy had to say:

In the TV frame of "Apollo 16" we "see" the snap being taken of the "jump salute" as we have called it. (62) The top of the flag in the TV frame is at approx. 70° from the vertical. Yet in the still photo of the same event (63) the flag is at a spanking 90° right angle. How can that be?

That can be because of (you guessed it) perspective convergence. Whether in photographs or on TV, objects viewed simultaneously do not happen in parallel, just as this book did not when viewed at close proximity in front of a mirror.

Book held edge-on before a mirror, with camera aimed at spine

Same book, same time, different views. You will of course note that the sides of the book are at 90° right angles (Do they come any other way?) while the top edge of its mirror-image has a sag of 70°. And I swear on a Bible I did not use any Photoshop tricks to get this picture.

"It is not possible to reproduce this effect relying on perspective convergence (an oblique viewpoint) for a similar result," huffs Percy with the supreme confidence that comes from never trying. Instead he tries to argue the point but succeeds only in refuting his own photo rule.

One might argue that the flag in the TV image is not square on, it is simply "pointing away". However if that were the case, the total surface area of visible flag would be considerably reduced. Whereas in these two pictures these areas are approximately the same, to within 10%. (Dark Moon, p. 43)

That's true enough, as far as it goes. My book-and-mirror picture shows a surface difference between images of nearly 100%. That's because the book is viewed square on, while its mirror image shows it pointing away at a sharp angle. But that couldn't have happened during the saluting scene. Percy correctly deduces that the flag had to be at the same relative angle in both pictures:

It must be remembered that these two images were recorded opposite one another. The TV camera was on the Rover which can be seen on the far side of the flag in the still picture (63).

With the cameras lined up this way, it would have been impossible for the flag to be oblique in one image and square on in the other. The flag must be oblique in both, or square in both. Confronted with these two alternatives, David S. Percy predictably picked the wrong one:

"So in both images the flag is virtually square on" (Dark Moon, p. 43)

Let's take another look at that flag in AS16-113-18339. Notice how square it looks. Notice how the stars are squeezed together in a field that's almost a vertical rectangle. Does that look like any U.S. flag you've ever seen? It looks much too square to be square on.

According to usflag.org, a proper U.S. flag has an aspect ratio of 1.9 to 1. However, Anne M. Platoff writes that the flags planted on the moon were 5 feet long by 3 feet high, so it should have looked roughly like the flag on the left.

Straight-on view of Apollo 16 flag - AS16-116-18576 (detail; flipped for comparison)

Here is how it did look when seen from the front. (For another full frontal of the flag, check out this panorama.) Note that even though the flag shows a 3 x 5 ratio, it still isn't straight. It sags from the pole at a less-than-spanking 88° and there's a large crease which bunches up the bottom. These little details played their part in creating the illusion.

In fact, the flag was at a sharp angle in both images. It was pointing away from the TV camera, and pointing towards Charlie Duke's Hasselblad. This tabletop model shows roughly how it and the cameras were oriented, with the cameras looking at each other and the flag at a sharp angle between them.

Tabletop model of camera and US flag angles during John Young's 'Big Navy Salute'

(This model comes from an earlier experiment that was more complex and less accurate than the one I did in this section. If it amuses you, you can check out the pictures that the cameras took on this page.)

The next pair of pictures show a more accurate flag model that I made by extracting the square-on view from AS16-116-18576 and printing it as a double-side. (Getting the paper to line up accurately in the printer was probably the hardest part of this sim.) (I could get away with using a reversed image for the opposite side, since flags under the sun show the same wrinkle pattern on both sides, but that's another story.)

The ruler represents the scale height of the flagpole. The lowest blue mark (just above my thumb) is ground level. The middle mark (at the 3½" level next to the Staedler logo) is the imaging plane of both cameras, or eye level when viewing this flag for the simulation.

The paper flag has its paper flagpole aligned with the ruler's edge, but you can see how it has a distinctive droop. That was the astronauts' doing, not mine: They deliberately left the crossbar hanging less than horizontal to give a nice "waving in the breeze" effect (never dreaming anyone would be dumb enough to think the flag was really waving).

The side effect of this aesthetic droop was that, when the flag was pointing away from the camera, the droop became sharply exaggerated. If you hold this flag with the 3½" mark at eye level and point it away from you, you will get an image like this simulation of the TV camera's viewpoint:

And when the flag was pointing at Charlie Duke, that droop was cancelled out by perspective, making the flag look shipshape and Bristol-fashion (if rather square).

In these two images, the flag was viewed at approximately 36° from the line of sight (or more precisely, one view was at 36° while the second was at 144°, which is pretty much the same thing). At this angle, the flag would appear only 60% as long, making a 3 x 5 flag look square. There's another way to verify that I held this flag at the same angle. The ruler in these images is exactly 1 inch (2.5 cm) wide. If you measure the markings and compare it to the width in the rotated images, you will see it looks 60% narrower.

Similarly, the Apollo 16 flag was also seen at the same sharp angle in both images. There are many angles at which to view an object, and despite the blatant photographic evidence, David Percy chose to believe this particular object was "square on." He chose poorly.