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

[Aniej]

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.

 

[lancestraz]

Are all of the files are text documents?

 

[Peace]

The compression ratio really depends on what's being compressed.

Movies don't compress as much as say , text.

 

[Sherman Homan]

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.

 

[Aniej]

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?

 

[lancestraz]

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.

 

[killmoms]

That's because PDF files often already employ compression. Anything that already employs some form of compression will not easily compress further.

 

[Aniej]

OK, I guess that's the answer then. Not the most wonderful conclusion, but I appreciate the info nonetheless.