Tutorial: Editing Photoshop .atn Files (Actions) with Java on the Mac

I’ve circled the “PbTl” in red in the screenshot above. So I simply selected the text and changed it to “GrTl”, saved the file with the .atn extension and held my breath. When I loaded it back in Photoshop (Actions panel fly-out menu > Load Actions) it worked like a charm and Select brush was now Select gradient (tool) – see screenshots below.

So what good is this? I don’t know and, right now, I don’t care. I’m a firm believer of following what interests you and whatever it is will probably come in handy some day. You never know when a tidbit of knowledge like this might fit with something else you’re working on. And it’s not that often we non-programmers get a chance to see behind the scenes, as it were.


Take a look at James Walls’ comment below to see how he used this trick. Thank you James for your input.

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James Walls:

Fantastic advice – and anything but useless! I’ve used this as part of porting my extensive actions(and associated scripts) from photoshop CS2 to CS3 – previously I’ve had to re-record portions of the actions to point to the right scripts directory locations, but this has enabled me to replace CS2 with CS3 in the file path within each action – saving me several hours of unwelcome rework. Thanks!


I was asked recently to do some hex editing on some ATN files at work. One of the graphics/design guys needed a way of replacing all instances of one string with another for an ATN that performed a bunch of actions and created a series of output files (I’m not familiar with PS so I don’t really know). There were dozens of instances of these strings, and the length of string was being changed so a straight overwrite wasn’t working properly.

Anyway, I wrote a tool to do this in Java, which I posted here: http://www.blinkenbyte.org/modifyatn/modifyatn.html

The page also contains some of the details about the two types of UTF-16 strings I found in the ATN files so you can perform the modifications manually if you like.

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