See this list for all available keyboard shortcuts:
There are nearly no shortcuts for adjustment controls however.
You can add shortcuts for all commands that are available from the menus, by using the command from the Aperture application menu:
Aperture > Commands > Customize
Leonie, Yes I have looked at all these resources and am aware of the customize menu, I couldn't find the command to close brush HUD in the list. Do you know if it is there?
I noticed that if I specifically choose the HUD window (click on the menu bar in the small HUD window so it turns lighter gray) I can close the HUD with the close tab command command+W
However that isn't much help as I can't seem to nightlight the HUD window without mouse clicking on it, and at that point I may as well just click the "x" to close it.
I couldn't find the command to close brush HUD in the list. Do you know if it is there?
I could not find it either.
I think, the only way to create a keyboard shortcut would be to create a menu command by writing an Automator Service, based on an Apple Script, that will close the HUD. Once you have it in the "Services" menu, you can assign a keyboard shortcut.
Or write feedback to Apple, to provide a command to close HUDs.
Have you tried pressing 'A' on the keyboard? This should change the brushes tool to the "Selection Tool" pointer.
I've just tested this with the brushes palettes in the 'brush icon' menu (retouch / skin smoothing etc) and brushing in adjustments such as Enhance and Highlights & Shadows. Works for me and is a great time saver.
In the simplest case -- where you have evoked a Quick Brush and used it -- you can close the Brush HUD by issuing the "Select Selection Tool" command, which is available as an icon on the Tool Strip, as well as by keyboard shortcut (customizable; the default, I think, is "a").
There are ways to make this unavailable while the Brush HUD is visible (all of which are, imho, design flaws), but the current implementation works well in practice. I have assigned keyboard shortcuts to all the brushes I use. I activate a brush with the shortcut, use the brush, and dismiss it (and the HUD) with a simple press-and-release of the "a" key.
I use a brilliant utility called Witch (from Many Tricks; Leech, Moom, and Name Mangler also highly recommended; of those, Name Mangler is likely of the most interest to Aperturists) (just a very satisfied customer). Among its many tricks, Witch lists all open windows (by OS or application), and allows the user to close them from the list. If you are looking for a way to control windows from the keyboard, I recommend spending some time with Witch.
What Adrian (mtb_monster) and Kirby said. It works great.
On the default keyboard, "A" is assigned to "Select Selection Tool". Pressing that key will close any brush HUD, as well as crop, straighten, and redeye.
You could also assign it to another key of your choice using "Commands" customization. I have it assigned to "X" since I moved a bunch of key assignments around to group them more logically than the default.