.zip has nominal file size reduction, am I missing something?

Discussion in 'Mac Basics and Help' started by Aniej, Jan 14, 2008.

  1. Aniej macrumors 68000

    Aniej

    Joined:
    Oct 17, 2006
    #1
    I have a folder with several files in it, about 75 in total. The documents range from a couple pages to almost one hundred pages. According to the "folder's info" the original folder containing the files weighs in at 101MB. After I ran "compress" from within finder the resulting .zip file produced was 94MB. This is a negligible size reduction so I was wondering if I am missing something in terms of a setting or anything else that would result in such a minor size reduction? Even a suggestion for a different compression application, if that's what you think might be the reason for these results, would be much appreciated.
     
  2. lancestraz macrumors 6502a

    lancestraz

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    Location:
    RI
  3. Peace macrumors P6

    Peace

    Joined:
    Apr 1, 2005
    Location:
    Space--The ONLY Frontier
    #3
    The compression ratio really depends on what's being compressed.

    Movies don't compress as much as say , text.
     
  4. Sherman Homan macrumors 6502

    Joined:
    Oct 27, 2006
    #4
    Compression totally depends on what is to be compressed. Sometimes you can .zip a jpeg or pdf file and end up with a bigger file! Or compress a Photoshop .psd file and see it collapse into a tenth of its original size.
     
  5. Aniej thread starter macrumors 68000

    Aniej

    Joined:
    Oct 17, 2006
    #5
    No, not in the sense that they are either .txt or .doc, rather most are PDF versions of text documents. Some of these PDFs contain pictures as well. The files are from several academic journals so I do not have the ability to simply use a .doc or .txt for the files in question. Thoughts?

    OK, comments 3-4, which were posted while I was responding to comment 2, give me a bit more insight. Is there a way to know what types of files will typically compress well, i.e., reduce in size?
     
  6. lancestraz macrumors 6502a

    lancestraz

    Joined:
    Nov 27, 2005
    Location:
    RI
    #6
    I compressed a folder with 100mb worth of PDF files to 75mb; but a folder with 100mb of text documents compressed to 17mb.

    PDFs don't compress very well, apparently.
     
  7. killmoms macrumors 68040

    killmoms

    Joined:
    Jun 23, 2003
    Location:
    Washington, DC
    #7
    That's because PDF files often already employ compression. Anything that already employs some form of compression will not easily compress further.
     
  8. Aniej thread starter macrumors 68000

    Aniej

    Joined:
    Oct 17, 2006
    #8
    OK, I guess that's the answer then. Not the most wonderful conclusion, but I appreciate the info nonetheless.
     

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