I have a background layer which contains an image. I'm trying to auto map the color of my brush to take the color of the background. Is this possible? The following video illustrates it better, starting from minute 1:30.
The feature "auto map the color of brush from background" is what "Art History Brush Tool" doing. You can select it by "Y" or "Shift+Y" key. And you will need a "History Brush". Standard brushes won't work, if you try to use them then the appropriate tool will be selected automatically and you can't use "Art History Brush".