The red window filters all colors emanating from the case except red.
If the interior is illuminated with a blue light, the red window will,
theoretically, produce black since it filters every color except red.
The red window filters all colors emanating from the case except red. If
the interior is illuminated with a blue light, the red window will,
theoretically, produce black since it filters every color except red.
Of course, if you've ever worked in a darkroom or what-not you might realize
there's quite a bit of variation in a transparent object's ability to filter
light.