Layer mask question

To create a black mask quickly, simply hold down the Alt key while clicking the layer mask button.

I just learned a keyboard shortcut for this operation so I thought I would share it here.  Simply click on the layer mask and  press Ctrl-I to invert it from black to white or vice versa.  I assume Cmd+I will do the same on a Mac machine.

1. Click the white thumbnail on the layer
2.  Select the Paint Bucket tool
3. Make sure black is the foreground color (toggle black and white by pressing X key)
4. Click on the image.

For future reference, you can use the Layer>Layer Mask>Hide all option to create a "black" mask.