So one of my commercial clients wants their product files in a variety of formats, including PNG with transparency. I'd love to be able to provide them with this from LR, but you can't export as a PNG. So I've written a script which takes the active document in PS, turns off the relevant layers, converts to sRGB, and saves as a PNG. Is there any way for me to invoke this script from LR, as I am opening the document? Ideally, I'd like to include it in the "Edit in" menu, as a menu item which would invoke PS and run the script. That way I could simply select the images, and get them processing while I do something else. Or do I have to open all the files and then run the script on all the open files?
While I haven't done this, but actually looking into it for a script I have, the start up file photoshop.jsx (now photoshop-2014.jsx, contains functions for starting scripts in Bridge and Lightroom and running them in PS. you just need to copy the set of functions for one of the other scripts like Photomerge and swap your info for your script.
Images are automatically saved back to the LR library but you need to follow a logical sequence for LR to render the export copy. You need to start the round trip from LR as follows and use the save command (Ctrl+S) not save as:
1) Ctrl+E in the Library to export selected image with develop settings (I choose PSD but tiff is also available in the prefs)
2) Edit in Photoshop; then Ctrl+S to replace (overwrite) Lightroom export copy
3) Ctrl+W to close in Photoshop and update Lightroom thumbnail. The saved copy is usually stacked next to the original so don't worry about XMP.
On Mac OSX Cmd+E; Cmd+S; Cmd+W