When you have an existing selection and you hold down the Option/Alt key, you can drag to subtract from the selection. Note in Figure 3-7 that the selection tool's cursor shows a small minus sign when subtracting from a selection.
i "Double-clutch" with the Shift or Option/Alt key. You can even constrain proportions or select from the center and add to or subtract from a selection. Press the Shift key (to add to the existing selection) or the Option/Alt key (to subtract from the existing selection). Click and start dragging the marquee selection tool. While continuing to hold down the mouse button, release the modifier key and press and hold Shift (to constrain proportions) or Option/Alt (to center the selection) or both; then continue to drag your selection tool. You might want to use this technique, for example, when creating a donut-shaped selection. Drag the initial circular selection, and then subtract a smaller circular selection from the center of the initial circle.
Don't be afraid to experiment with modifier keys while working with tools.
After all, you always have the Undo command (^+Z/Ctrl+Z) at hand!
Was this article helpful?