Pressing Alt (or Ctrl for that matter) while a Photoshop action is playing has no effect on the action. It will play uninterrupted until it ends or encounters a command with the modal option turned on or one that conditionally pauses like a mode change command.
Pressing Esc will interrupt a running action.
Are you making the observation that Photoshop acts differently than other programs? I guess I’m missing the point you’re trying to make or problem you’re trying to solve. I’m a little slow sometimes.
Would you provide some additional information/clarification?
My action includes a Last Filter step (Control+F). I run USM, choose settings appropriate to the image resolution, undo, then run the action as a batch action on a folder of files. This way, all images get stuff done to them, including the USM I want. Normally, if I press Alt any time while the action is running, the filter pauses at that stage (as if I turned my Control+F into Control+Alt+F). Actually quite useful. But, that Alt key sensitivity should only be used when Photoshop is the frontmost application. As it is, if I switch to another program and have the Alt key down when PS gets to that step, PS will pause, waiting for input.
Very interesting, Scott.
Now that I’ve tried it I can see how the ability to selectively pause an action "in flight" (and be able to populate a dialog and resume) could certainly come in handy.
Chalk one up for learning something new and pretty amazing today.
RE: Alt key behavior
I suspect the "regardless of what application you’re in/pressing alt pauses a PS action running in batch" is a Windows issue. I’d be surprised if our Mac colleagues experience the same symptoms.
RE: Select last menu item command method
I understand what you’re doing and why it would work.
What’s not clear to me is what’s the advantage over recording a USM command in the action initially and, before subsequent runs, just rerecord it with new settings.
I have a feeling I’m going to be enlightened twice today with your reply!
Bump… hoping Scott checks in.
Looking for his comments on the merits of recording "Last filter used."
First, I use a decent flatbed scanner to scan up to 100 photos all at the same resolution. Next, I clean them up with stamp/heal/other tools. Finally I run a colour correction/conversion/sharpen action.
That last stage can be run manually, with a pause at each step, or automatically, by turning off the dialogue boxes for each step (remarkable increase in productivity, acceptably minor loss in quality). That works fine for curves, shadow highlight, convert to profile, and selective colour. But not for the USM.
I chose to use two steps for USM, turning one or the other off depending on how automated the action should be. One step is an unrecorded menu selection (Insert Menu Item from Actions flyout) of USM. As such, it always uses the last settings, and always pauses for input. The other is a Control+F (Select Last Filter), which I use after I have set up USM with the settings I want. Do I’ll run the action in manual on photo number one, then on automatic for the rest.
Now that I give it some consideration, I don’t know that my method is superior to a recorded USM that I have to change (double-click on action step) as required. It would eliminate the occasional trap I fall into whenever USM was not my last action.
