More Mysterious Forces at work: using Mac OS to repair corrupted JPEG and EPS files

In yesterday’s blog I revealed that I can “convert” PNG files to TIFF files just by changing their suffix in the operating system. In fact no conversion is taking place; the file name is being changed, and that’s it. Somehow Photoshop can open a TIFF file that is actually a PNG file (or vice versa) due to the fact that the file structure is similar.

Today’s Mysterious Forces adventure is more complex, and more mysterious.

My wife, a graphic designer, received a handful of files on Wednesday for a four-page newspaper advertising “wrap” ad. Several of those files were corrupt. One of them was an .eps file, probably from Illustrator, and the others were corrupt JPEG images, none of which would open in Photoshop, but all of which would display correctly in InDesign (strange!).

She needed to open the JPEGs and at least look at them, to be sure that they had no repairable flaws. But she could not open them.

So, following the advice of local Mac guru Justin Sharp (mentioned in yesterday’s blog), I removed the suffix from each of the offending files (using Get Info). When you attempt to remove the suffix from a file, the operating system challenges you: are you really SURE you want to do this?

And, I did it, leaving one of the JPEGs with no icon, and no suffix sitting on the desktop.

When I double-clicked the icon, Mysterious Forces went to work on the file, creating a duplicate file with a JPEG suffix, and a correct icon showing the image of the document. This took just a few seconds.

When I double-clicked on the new document, it opened in Adobe Photoshop, and was no longer corrupt. The original file is still corrupt.

I tried this with the corrupt .eps file also, removing its suffix altogether, and then double-clicked on the orphaned icon. As with the JPEG, the file opened immediately in Adobe Illustrator, intelligible and as originally intended.

I am amazed by this, and I have no idea who/what is doing the work. Is it the operating system? Is it an Apple Event? Is it some tendril of Adobe Photoshop or Illustrator? Is it Preview?

Whatever it is, it works, and it solved the problem of the corrupt files.

By the way, I was able to open one of the corrupt JPEG files in Graphic Converter, the shareware graphics application that we all seem to have in our Applications folder. The others would not open in that application. None of the corrupt files would open in Preview, Apple’s low-end image application.

About Brian Lawler

Brian Lawler is an Associate Professor of Graphic Communication at California Polytechnic State University, San Luis Obispo. He writes about graphic arts processes and technologies for various industry publications, and on his blog, The Blognosticator.
This entry was posted in Photography, Photoshop techniques, Software. Bookmark the permalink.

2 Responses to More Mysterious Forces at work: using Mac OS to repair corrupted JPEG and EPS files

  1. Hi again. My vote is for the OS (which version gets the credit?). Stripping the extension may have told the app to ignore the metadata, which is probably what was corrupted, or might possibly have been infected. You’d be able to tell this if the metadata in the successfully-opened document was blank. On to more entries by you . . .

    ECS

  2. Adam Moos says:

    I was hoping I had found the answer to my problem…Alas, the fix is not working for me.

    My daughter returned from a school trip and lost about 1000 photos when iPhoto crashed. Deleted the photos from the SD card only to realize the transfer did not take place.

    I used Wondershare to recover the files from the SD card. We did well. There are about 100 photos that are coming back as corrupt (as above) from Photoshop. I tried the remove extension fix but it did not work. When I remove the extension, the file comes back as a “terminal” file. When I try to open it in Photoshop, the program tells me it does not recognize this type of file.

    My daughter is grateful she has 90% of her photos. However as her Dad, I’m trying to fix what is broken. Any help/ideas you can offer are greatly appreciated.

    Thank you.

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