Re: Purple spots on pictures?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Adam,

When a digital camera is used with long shutter times in the dark, you may 
get "hot pixels".  A web search for that term will tell you the whole 
story, but basically they are just pixels in the camera's sensor that have 
more background noise than others.  Trying to take another picture in 
similar light and shutter speeds but without the coil will tell you for sure.

Here is a picture by Garry Freemyer that really pushed the hot pixels to 
make an interesting picture! (3Meg file):

http://hot-streamer-dot-com/TeslaCoils/Misc/GarryFreemyer.bmp

If you lighten the picture, it makes a cool star field thing that makes 
nice background!  Other smaller pictures showing the effect are at:

http://hot-streamer-dot-com/TeslaCoils/Misc/FreemyerPics/Tesla_010203-004.jpg

http://hot-streamer-dot-com/TeslaCoils/Misc/FreemyerPics/Tesla_010203-006.jpg

Cheers,

         Terry




At 05:50 PM 5/23/2003 -0700, you wrote:
>I just got back from taking my tesla coil to school (everyone loved it, of 
>cource.) And my teacher took a bunch of pitcures of the coil in action. On 
>all of the pictures, these purple spots appear on the pictures. They are 
>digital. When he took the pictures, he left the shutter open for 1 second 
>to get more streamers on camera. In one of these pictures, there are 4 
>purple dots that appear to be a particle that flew off the top load and 
>fell to the floor. does anyone know what these purple (and sometimes red, 
>white, and blue) dots are? Is it just the digital camera screwing up?
>Thanks
>Adam  KD5WIT