Nology)

[Raymond C Drouillard]

On 01 Jan 99 21:13:41 +1200 "Tom Parker" <tparker at nznet.gen.nz> writes:
>Bill the arcstarter <arcstarter at hotmail.com> wrote:
>
>[killing speed camera photos]
>
>>Oh - that sounds nice.  I had thought about a constant IR lamp blaring
>>on the plate to fog the film.  Possibly via infrared leds/diode
>>modules...  Most b/w film is sensitive to IR or so I'm told...
>
>This might work, but I would think you would need a rather powerful
source.
>In order to completely burn out the film  you need a huge amount of
light, I
>have got usable images from film overexposed by 3 or 4 stops.
>
>I imagine a flash aimed at the number plate would be most effective. If
the
>flash is pointing at the camera, and is near the plate, you might have
some
>luck, but the camera will be doing its best to keep the light from the
flash
>in the area of the film where the flash is, not where the plate is. You
would
>only get light that is scattered inside the camera going from the flash
to the
>image of the number plate.
>
>At least, this is how I see it.
>
>The other problem with slave flash units is that they are very
sensitive. If
>they see any kind of very fast rising light source, they go off.
>Photographers have problems with slaves triggering off strobes in shop
windows
>far away from where they are photographing...
>
>The local police claimed that the idea would not work. They didn't give
any
>convincing reasons for it. They went on about how fast the shutter is,
but the
>flash is much much faster...
>
>--
>Tom Parker - tparker at nznet.gen.nz
>           - http://www.geocities.com/MotorCity/Track/8381/
>

I would point the flash at my plate to avoid being accused of blinding
other drivers.  Also, since my plate is blue with white letters, I would
put a blue filter on the flash to reduce the contrast between the letters
and the background.  Another option would be to project an image on the
plate with the flash.  If it is lit with blue light that has a mottled
"texture", it would be extremely difficult to read.  You wouldn't need to
use enough brute power to wash out the film, that way.  Just obscure the
image.

Ray

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