Picking Colors with the Brush Tool in Photoshop and PSE
When you are working with digital brushes, the Foreground color is the color of your “ink.” There’s a simple way to change “ink” colors on the fly while you have the brush tool selected. Simply press and hold the Alt key (Mac: Opt key) to temporarily activate the Eyedropper tool. Click on your document to pick up a new color, then release to return to the Brush tool again. Using this method, you won’t have to stop and change tools to change your brush color.