We recently installed a cctv system in a very up market bathroom design shop. They had four black and white cameras on the shop floor and two observation monitors - one ceiling mounted near the entrance showing the pictures from the camera on the entrance doors. This meant that as customers walked in they could see themselves on the monitor. The other monitor was mounted near the reception area where customers paid for their very expensive new bathrooms.

The day after installation the manager phoned me in very hushed tones to say there was an embarrassing problem with the cameras. I coaxed out of him that if any of the female shop assistants were wearing black underwear that it showed up on the monitors. Worse still when his up-market female clients walked into the store the first thing that greeted them was images of themselves on the ceiling mounted monitor, with their underwear on display to everybody.

I found it very hard to believe and told the manager I would go there myself to check the system. I consulted my senior engineer about the problem and within 5 minutes I had four engineers on the phone saying they were 'just passing the store and if there was a problem they would be more than happy to call in and check it out' Hmm I wonder why?

Anyway I took an engineer to the store and sure enough the female assistants were huddled behind the counter with their arms crossed not daring to come out and when we played the images back it was like looking through supermans eyes as all you could see were the bras and pants of the poor customers and assistants - one of whom had been showing her thong to the whole shop!

I'm sure this isn't the point of the story but if anyones interested the see through images were caused by high levels of background infa red (posh lighting in the store) and the problem ceased as soon as we swopped the mono cameras to colour.

If anybody wants to buy the tape we salvaged from the store it can go to the highest bidder!

Helen

Hi Helen,

I bid £5!

You can get the same (but better) effect with Ultra Violet lighting as well

Similar effect is seen if you look at a CCTV image of a fabric covered Loudspeaker, you can see the drive cones showing through.

How does that work then?

If you have a large IR source and a BW camera it causes this effect?