Finale advice before I start

[Ian]

You will have come across gain before, but not called that.

The volume control on a stereo is a gain control. If you set the gain up to the higher end of the slider, the image will be lighter, if you move it down the other end, it'll become dark. One thing to note is the once the webcam is showing white, it's at a maximum and you'll get no more image adding more gain. So one of things you need to do once you've got an image from the camera is to adjust the exposure and gain to get the brightest image without hitting the maximum. Another term for that maximum is saturation, which you'll probably read about.