Squiggly lines. Tracer? Squiggly?
I have this picture on my PC, it’s readily findable on the ‘net, and is attributed to the Imperial War Museum but clearly out of copyright these days.
It is probably/presumably a target photo that happens by chance to have caught the silhouette of a Lancaster not far below.
But I keep coming back to a puzzle. What are those squiggly lines? And if they’re tracer, why aren’t they an arc? I would have thought looking down you’d see tracer as an arc – up towards you then falling away? Are they perhaps something else?
cheers D
By: 25deg south - 30th November 2007 at 08:04
One of the more unusual Photo Interpretion tasks in the U.K. in WW2 to analyse this type of imagery in order to establish the constitution of enemy air defences. It was quite an art apparently, but fairly succcessful.
By: Creaking Door - 30th November 2007 at 01:30
The camera contained a roll of film for about twelve exposures and was timed to expose them in ‘quick’ succession at approximately the same time as the photoflash would explode. The idea being that one exposure (at least) would coincide with the photoflash and give a good target photograph.
Don’t know what that means in terms of length-of-exposure…just my thoughts. 🙂
By: Eddie - 30th November 2007 at 00:46
I don’t know the precise details of how the cameras were used, but – imagine it as follows.
The shutter is open for say, 5 seconds… All of the long squiggles are lights of one kind or another that are illuminated throughout that 5 second exposure (or perhaps, in the case of some of the “partial squiggles”, say a second). The Lanc is actually being illuminated by a large bomb burst (a cookie?) or a photoflash bomb which would only be a fraction of a second, hence the sharp exposure. Does that “bring things into focus”?
By: Smith - 30th November 2007 at 00:24
Ahhh … maybe I guess … how long an exposure would this be? I’m still struggling a bit with the whole of the image.
How is the single clear exposure of the other aircraft explained – wouldn’t we have a ghosted image? Is the camera aircraft effectively “panning” the lower one in this photo? But wouldn’t their relative movements be all over the place? Is this an exceptionally rare clear exposure – a fluke of chance?
Or maybe I’m just missing something here – I’m no pro photgrapher.
By: Eddie - 29th November 2007 at 00:52
Just to “prove the point” about them being due to the movement of the aircraft, I’ve highlighted several of the trails that share the same shape. The reds are all the same trail (or portions thereof), green another trail, etc etc. The explanations for the different shapes would be that they were illuminated at different times in the exposure.
By: Smith - 29th November 2007 at 00:25
Hi Gnome – we always seem to end up in the same threads, don’t we?
Time zone maybe 😉
Thinking about your long-exposure point. There’re a number of squiggles behind and to port of the Lanc in the photo that share the same shape and I can see how they could be tracer arcs (rising up then falling away) captured by a moving camera. There would be a lot of turbulence over those fires.
But that doesn’t explain for example the smooth bright arc at bottom left of the picture.
Also I note some of those lines seem perfectly duplicated. Twin tracer? Or are there two exposures on this image?
By: Eddie - 28th November 2007 at 23:42
Hi Gnome – we always seem to end up in the same threads, don’t we?
These target photos were taken on a long exposure – if you notice, most of the squiggles share the same shape, so they were presumably fires on the ground, searchlights, or some other light source, and the squiggles are just because of the manouvreing of the camera aircraft. The Lancaster is sillhouetted by either the blast of a cookie (that’s my guess) or a photoflash flare. Up to the top right there appears to be either some tracer or a dripping TI. I think it’s a TI, but it’s just a guess!
Incidentally, that is the cover photo on the Cassell print of “The Battle of Hamburg” by Martin Middlebrook.
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November 28, 2007 at 11:29 pm