Hello,
I'm guessing that you may have either purchased CCTV cameras featuring either a CMOS chip, or a generic 1/3" or 1/4" CCD. If this is the case, then you I would recommend that you step up to a color camera featuring a 1/3" Sony CCD like the
KG-230 series.
Other suggestions would be to adjust the camera (and sunscreen if applicable) so that the camera does not point in the direction of the Sun, or source of bright light or glare. If you are using a DVR, see if you can adjust the camera properties and lower the brightness of the camera.