There is a lot of confusion about the usage of red light for chameleons around the groups and forums.
While it is totally pointless to use a red bulb at daytime, as the red color light is absolutely unnatural (it can not be found anywhere in the nature except of as an integral part of the full spectrum of the visible light) and thus using it, is a complete nonsense, that I almost refuse to comment, the use of it at night is questionable.
Some red lights have been designed for nocturnal species for people to see them at night spreading the belief, the nocturnal animals can not see it and they do not mind it. It is just fake and a parody of the military- and industry-used infra-red light night vision, which, using specific filters, makes the heat radiation of objects (including animal or human bodies) visible for human eye. You see the difference? A light emitted by a red bulb is not infrared but RED (with some infrared parts) and is visible by the very weak human eye not using any special lenses nor night-IR-vision device. So, the animals CAN see the light as well!
So, there are two questions actually:
1. Do the nocturnal animals see the red light emitted by these red bulbs? And the answer is: YES!
2. Do the nocturnal animals mind the red light emitted by these red bulbs?! And the answer is: NO, they do not mind if the intensity is very very low. The moon is reflecting under 4-5 lux, as such, if we provide light of any and all colour over this qty we interrupt the standard rhythms and cycles inc the D3 cycle. Due to environmental home lighting it may even be prudent to cover cages after lights out.
All this is true for NOCTURNAL animals, means animals active AT NIGHT.
Now, chameleons are DIURNAL animals, they are active AT DAYTIME. So, the situation is completely even more complex!
You do not need it plus it IS harmful at night for chameleons, so do not use it!
Why is that...
The third eye, that is called parietal eye is capable of detection of a wide spectrum of light from IR through visible spectrum to UV at low intensities. It is connected to a special organ, called pineal organ, laying underneath. The poorly studied organ yet is i.a. responsible for the control of the sleep. So even when the eyes of the chameleon are closed, it does not allow him to sleep fully if it detects visible (even red) light.
If exposed at night to red light long term, the chameleon can get exhausted from not enough sleep and starve to death...
So, the rule is: never use red light at night!