Reduce PDF file size ...

Question

Reduce PDF file size ...

HI,

I have scanned a 15 page documents in Gray Scale with my HP OJ G85 and saved it in PDF. The size of the document is 7.9MB.

With Apple's PDF Preview, I tried to reduce the size by using differents filters. With B & W the file increased to 11.9MB (???). With Reduce Size, the file size was reduced but the result is difficult to read.

Recently I received a PDF document of 22 page. The result was cristal clear and the size of the overall document was about 550KB.

What is the best strategy to get a PDF document with many pages to a size I can easily send by email ?

Thanks in advance.

Robert Lespérance

Happy owner of an iMac G5 !!!!, Mac OS X (10.4.10), 1.6 GHZ - 17" - 2.0 Go

Posted on Nov 12, 2007 6:37 AM

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Answer 1

Nov 12, 2007 9:21 AM in response to Robert Lesperance

The pdf format converts text into code which can be reconstructed by the reader to replicate the original document. Images are converted into formats which may lose information if you choose to reduce the file size. Your problem comes from the fact that you are scanning your document, which makes it one big image for each of 15 pages. There is no text. By reducing the file size, all you are doing is degrading the quality of those images.

If you want to reduce the file size without reducing the quality of the text, you should run the document through an Optical Character Recognition (OCR) function to convert the writing on it into editable text. This process is reasonably, but not 100% accurate these days, and usually will not retain the exact layout of the document. Once you have done this, the file size will be much reduced and the text can be scaled without loss of detail. However, this is a lengthy process, and the results may not be what you want. The best way to get make a pdf file is to convert it directly from the original electronic file.

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Answer 2

Nov 12, 2007 1:17 PM in response to Robert Lesperance

Hi Robert: I'm not sure what kind of document you need to scan, but have you tried scanning in B/W as opposed to converting after the fact? It should create a smaller overall file size.

Stedman

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Answer 3

Nov 13, 2007 10:26 AM in response to stedman1

Hi Stedman,

Scanning B & W or Shades of Gray did not change the file size.

I found a solution .... I remembered that we can modify PDF's Quartz filters in Automator. The function/task names that I give are litteral translation from french and may differ with what you actually see on your computer.

It is not obvious. Create an new Automator processus with the «Apply quartz filter». In the 2 processus to the right, open the «Advanced Options» and you should see all the PDF filters. Click the black triangle to the right of the Reduce File Size filter and choose the duplicate filter option. In the Image sample put the resolution to 150 DPI, put the quality to low and empty all other items. In the Compress Image put also the quality to low.

By doing this you have created a new PDF filter that will be available in the PDF Preview's Save as window that should give you a very good quality while reducing substantialy the size of your document. My document of 43 pages reduced from 25MB to 3.8MB. Enough to be sent by email.

Any other PDF application (PDF SHRINK - PDF COMPRESS etc ... ) did not give any result to reduce the size of my file.

I wonder why a feature like this is not standard in PDF Preview .....

Hope this helps ..

Robert

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