Why does the window or bubble of a bullet or dome camera turn yellow over time?

Question

Why does the window / bubble of a bullet or dome camera turn yellow over time?

Answer

For bullet and dome cameras the clear window / bubble is generally made out of polycarbonate with a special hard coating to provide scratch resistance.

The window / bubble is susceptible to wear by prolonged UV exposure which materializes by yellowing the material over time. To limit direct UV exposure to the window / bubble, it’s recommended to always apply a weather shield to cameras installed outdoors:

The automatic white balance algorithm of the camera will compensate for the changing tint of the window / bubble, but at a certain point image quality impact might not be acceptable anymore after which it can be replaced by a new window / bubble available through Bosch as a standard replacement part.