Why is the blue filtered light bad?
The blue-green filtered light that some of the military is using is secure because it is not seen as easily with the NVGs as the white or red filtered light, but it is still dangerous. It is dangerous because it distorts color. Like the red filtered light that washes out all of the red and reddish colors on a map, the blue-green filtered light washes out all of the rivers, roads, boundaries, contours, and declinations that are greenish or bluish in hue. You cannot afford to misread your map. In addition, blue green filtered lights are very tiring on your eye.
