File size Doubling when "duplicating" or "exporting" in Lions Preview app. WHY?

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I noticed today while duplicating a file for testing purposes that the file size is more than double than the original. I tried exporting it while keeping it in the same file type and it did the same thing as well.

original file size = 155.4
duplicated file size = 353.7
exported file size = 353.2

Any one know how to make copies with out increasing the file size so much? these are large blueprints that i use on my iPad 2. The large file size make them hard to use in the first place. I don't need them any bigger.

Thanks, Cody
 
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I noticed today while duplicating a file for testing purposes that the file size is more than double than the original. I tried exporting it while keeping it in the same file type and it did the same thing as well.

original file size = 155.4
duplicated file size = 353.7
exported file size = 353.2

Any one know how to make copies with out increasing the file size so much? these are large blueprints that i use on my iPad 2. The large file size make them hard to use in the first place. I don't need them any bigger.

How exactly have you been making copies? Exactly what kind of file is this? Have you not tried copy/pasting in Finder?
 
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How exactly have you been making copies? Exactly what kind of file is this? Have you not tried copy/pasting in Finder?

normally, while working with this pdf file, i would do a file/save as and name the file with the date saved. in lion save as has been replaced. duplicate and export is not working like save as did.

i know all about the "version" thing in loin, but i am saving a copy of this file on an external hard drive and emailing them to my boss.

i just wanted to know why export and duplicate change the file size so much.

Thanks for any help, Cody
 
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normally, while working with this pdf file, i would do a file/save as and name the file with the date saved. in lion save as has been replaced. duplicate and export is not working like save as did.

i know all about the "version" thing in loin, but i am saving a copy of this file on an external hard drive and emailing them to my boss.

i just wanted to know why export and duplicate change the file size so much.

Thanks for any help, Cody

Ok. I had the same thing happen. When you first open the document, it is ready to be edited and Preview is rendering it with its own technology, filters, what have you (sorry… I'm not technically knowledgeable enough about this to explain better). When you are saving it, even though you made no changes, Preview is "processing" the file into a new one using its own rendering engine. It isn't technically the same as copying it. This happens too in Adobe Reader (which is not yet compatible with the new Lion features), though in the test I just ran, it didn't bloat the file as much as Preview does.

MS Word documents are know to bloat up and up in size because the document retains a history of every change made to it for the "undo" function. One tip I had read years ago said to take one of these giant documents, copy everything, paste it into a new one and save it, and you'd have a much smaller file size for what otherwise is the same document. It's all that accumulated junk that you don't "see" that was bloating the file size.

As for Export and Duplicate… same thing. When you export it, you are having Preview process and re-save the file. Duplicate just re-opens the file in a new instance, but you still are processing it when you save the duplicate. The only way to get a proper copy of a file is to copy/paste in Finder.
 

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