Does renaming a jpeg file re-save it?

Question

Does renaming a jpeg file re-save it?

I have a significant number of jpegs in my collection, and want to do some wholesale renaming of the files. Understanding that any re-saving of a jpeg file reduces its quality, does renaming a master through Aperture also re-save it?

Thanks

iMac G4 - 17 / MacBook Pro (Penryn 2.4), iPhone 3GS, Mac OS X (10.6.6)

Posted on Feb 24, 2011 10:46 PM

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Answer 1

Yer_Man

Level 10

165,924 points

Feb 25, 2011 12:16 AM in response to Max Tomassini

Are you renaming the Files? Or adding a Title?

Regards

TD

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Answer 2

Ir. Bob

Level 2

346 points

Feb 25, 2011 12:39 AM in response to Max Tomassini

The image only deteriorates when the JPG compression is newly calculated. Thus when opening and saving in an image editor (e.g Photoshop). Renaming a file is physically the same thing as moving a file. This will not alter the contents of the file.

Furthermore, Aperture will never write anything to your master files, except when you specifically tell it to. Even then, these write actions to the master are limited to metadata and filename. None of those will trigger 're-compression' of the image and thus will do no harm to your JPGs.

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Answer 3

Feb 25, 2011 7:41 AM in response to Yer_Man

Will likely add titles as well, but my inquiry was specific to renaming files. Thx.

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Answer 4

Feb 25, 2011 7:54 AM in response to Ir. Bob

Bob
Right now, I'm concerned about duplicate file names given the volume of digital images I have -- IMG_0050 may appear twice having shot through 10k images on my camera, for example. Since I don't want to be moving or renaming files through the finder (everything should be done through Aperture, right?), I want to make sure than any file renaming I do via Aperture doesn't essentially re-save (and recompress / degrade) my image. I believe you answered that later concern (renaming does not re-save), but your response that Aperture only changes metadata and not master data is confusing. Does your response mean that if I was to rename the file via Aperture, and I was to go to the referenced master via finder, it would still have it's old (unchanged) filename? That doesn't sound right to me. Can you clarify?

Thanks again for your help.

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Answer 5

Ir. Bob

Level 2

346 points

Feb 25, 2011 10:35 AM in response to Max Tomassini

What I was trying to explain is that Aperture will never touch your master in anyway. However, in a few circumstances Aperture can actually modify your master, but then you have to tell Aperture specifically to modify the master and not only the database. The two things Aperture can alter in your master is it's metadata and its file name. Never, ever will it modify the image itself.

In your case, this means that in the 'Batch change' dialog you have to check 'change master filename'.

Ps every write action has the potential to corrupt files however minimal that chance is, you might want to backup before you start your renaming process

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Answer 6

Feb 25, 2011 12:36 PM in response to Ir. Bob

Good advice. Thanks for the clarification.

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Answer 7

Feb 25, 2011 1:45 PM in response to Max Tomassini

Max,

Aperture is much smarter than that, and differentiates not only upon the file name, but other meta-data, including the date and time. So no worry there.

You can rename as your import from the memory card, and you can rename when you Export, but not within the filing system.

Ernie

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