This question came up on a discussion on the Yahoo Group ASMPproAdvice (if you’re not a member, and are serious about the business of photography, I highly recommend it). When opening a picture in Photoshop from Aperture (using the “Open in Editor” command), what IPTC and EXIF data is retained, and what is lost? So I decided to do a little test.

For the IPTC fields, I entered in the name of the field for each one (except date and time fields require actual date and times, so I just put 2010-01-01 and 12:00 for those). For EXIF, of course I couldn’t fill in the blank fields, and there are several blank fields in my test file, so it’s not exactly a perfectly scientific test. But, it does show some interesting results.

Red dots are data lost; orange dots are data changed (but as you can see, all changed for a good reason). Click either image to open it full size. NOTE: You’ll likely have to drag the picture out of the pop-up window and open in Preview or whatever to view the whole thing… the pop-up windows here don’t get a scroll bar by default and I’m not sure how to add them.

IPTC data fields on original in Aperture, and after it’s been sent to PhotoshopEXIF data fields on original in Aperture, and after it’s been sent to Photoshop

As you can see, there’s almost no loss. The Audio metdata is gone from IPTC, but since these aren’t audio files that makes sense. Some camera EXIF data like Serial Number and Lens Model is gone, which I find curious. The Pixel Height and Width change is also curious but probably more to do with Aperture’s reading of the file (in this case an Olympus EP-P1 JPEG). If you look at Pixel Size, that’s actually accurate. It’s these other Height and Width fields that are funny. But sending the file to Photoshop actually fixes that.

Anyway, there you have it… for anyone wondering (or incorrectly stating) what metadata is kept intact or thrown away, there’s a somewhat-complete answer.