Not to steal this thread, but why is it green that is always used for nightvision? Couldn’t any other color be used? I have nothing against green, just wondering why everyone seems to have standardized on it for night vision.
According to this article:
There is a distinct difference between Night Vision and Infra-Red. Night Vision utilises tiny amounts of ambient light and amplifies it. In my experience it is green in colour. Infra-Red detects heat energy that is radiated or reflected from objects and is generally black and white.
Infra-Red is monochrome because it is measuring hot/cold, it could be shown in more colours, but only by assigning different heat values to different colours, it would have no basis on the actual colour of the object.
Night Vision is monochrome because it is measuring the brightness of the light. Also it only picks up light in the near infra-red range and at the red end of the visible spectrum, ie it does not pick up colour as such. The colour itself comes from the green phospher screen being used, I guess they could use other colours if necessary.
Night Vision is easily saturated by bright lights where-as IR can be used very effectively in daylight.
Because NV detects light in the near IR range, an IR light can be used to “illuminate” the scene if the ambient light levels are too low, however, the scene will still appear green as it is still being viewed on the green phospher screen.
scr4 is exactly right, Yellow-green is about the easiest to see and has the advantage of not being as visible to other imaging systems. As Skogcat mentioned the peak sensitivity is in the near IR and falls off fairly sharply as you go up or down the spectrum. There is always some light leak around the eye cup. I worked in the product engineering group pf one of the largest manufacturers of night vision and target designators for the US military until just s few months ago, we supplied much of the equipment that is in current use by our forces. By the looks of the images that I have seen the cameras being used are not the latest and greatest, there is considerable roll off of the image towards the edge and the image does not fill the screen, note that the full screen shots show a round image with a feathered edge, not filling the corners. The equipment in use is of good “commercial grade” but not state of the art “MIL-Spec”.