How to Compress a Large PDF on Mac Losslessly?

2017-05-03 21:27:07 / Posted by Rosa Reyes to PDF Follow @ Rosa

PDF, a powerful and versatile format to share documents across different systems and devices, is mature enough to extend its worldwide influence on shaping our office work.  If you’re working with PDFs on a daily basis, you are definitely enjoying tremendous benefits for a boost in productivity, but you might be also experiencing the same disturbing problem of compress pdf on mac when using a large size PDF. This is not a rare case, it happens on all of us and push us to shrink pdf files without losing quality for different purposes. 

My Own Trouble with Large PDFs and Why You are Not Alone?

The problem with large PDF I was experiencing was “repeated failure to send out the emails with large PDFs as the attachement". Back to those days, I was working with our customers to confirm details for business orders, like contracts, technical documents and package designs. Documents like these require high on quality and include many pictures, they have no way to be any smaller. Even worse, there is a strict size limit for our customers to receive emails in their country. The failure message in my mail box resulting from large PDFs annoyed me so much. 

And I know, I am not the only one ran into such a problem, neither you. Take a look at the following to check how similar situation so many PDF users are in now or before:

I have a 5 MB PDF file, I need it to convert into something smaller. I only have PDF Reader, I have no Adobe Acrobat or whatever. What is the best way to do that? What is the best way to convert it into smaller size?  --- Jamblebee from Gizmo’s
I wanna send a pdf file which is of size 59mb via e mail..But the network service can support for only 20mb of attachment.Anybody plz tell me how can i compress the file to within 20mb?   ---Lk_radhika from Yahoo Answers
Hello. I have a pdf file with lots of high-res photos in it. Is there a good way to reduce the file size while keeping the photo quality reasonable? A free utility that allows users to adjust the level of photo quality would be great. Under Preview, I tried "save as" and then "Reduce File Size" with Quartz filter. The file size was reduced by 1/10 but the photos did not look good.  ----hajime from MacRumors


Get to Know 2 Types of PDF Compression

For sure, what we care the most about PDF compression, is the quality. There are 2 types when we talking about file compression, the Lossless Compression and Lossy Compression.

Lossless Compression, the compression that can reduce files size without any loss of file information during the compression. Lossless compression is perfect for documents that any data loss is intolerable. Like, ZIP compression, a Lossless compression that can detect patterns and replaces them with a single character; also the LZW compression (Abraham Lempel, Jakob Ziv and Terry Welch-creators of LZW), is quite ideal for files including lots of repetitive data.

Lossy Compression, the compression that will reduce file size by permanently deletes any unnecessary data of the file. Let’s say, the JPEG compression (Joint Photographic Experts Group)is often applied for grayscale or color images if you think the lost quality on images is tolerable.

How to Compress a PDF on Mac Losslessly?

The first, also the only recommended solution is using Cisdem PDF Compressor. It is the easiest way to shrink pdf on mac without losing quality and save you a lot of detour. You can choose between the Minimal, Small, Medium and Large pdf compression mode to decide a lossless compression or lossy compression. Also the Cisdem PDF Compressor will show you the real-time PDF file size under different PDF compression mode, you can easy view the difference in quality as compared to the original, as well as the compressed PDF file size.

Free Download

  1. Add PDF Files that You Want to Compress.
    Launch Cisdem PDF Compressor Mac. And then drag and drop PDF files that you want to compress on mac to the application. It support batch compressing to compress a pdf on mac 01
  2. Choose Different Modes to Compress a PDF on Mac as Needed.
    Cisdem PDF Compressor Mac provides you with various different ways of compressing PDF documents - Minimal/Small/Medium/Large File Size with different dpi. Still, you can customize the settings under different compression modes. Also, you can check the real-time reduced size of the file under different compression to compress a pdf on mac 02
  3. Start Compressing A PDF on Mac.
    Once you have completed all the necessary settings and preparation work, please click on the “Compress” to start to compress pdf on to compress a pdf on mac with cisdem 03

How to Save You From Compressing A PDF on Mac? ---Creating Small PDFs.

There are several factors deciding the size of your PDFs:

  • The image resolution;
  • Image type(bitmap or vector);
  • Numbers of fonts and how they are embedded;
  • PDF version(the higher the version, the smaller the file in general);
  • Number and complexity of forms;
  • Use of multimedia;

You can use these techniques and tools to create your PDF as small as possible.

Optimize Existing PDF: Many PDF are not fully optimized at the first beginning. Use the optimizer to resize the existing PDF first if you don't require high on PDF quality.

Prefer Vector Graphics---Vector-based graphics can make GIFs images, and take up less space than bitmapped graphics. You can also resize the vector image by using ZIP compression that is built into the PDF format.

Use Minimize Fonts---Each extra fully embedded font will take another 40K in PDF file size, so use as less as possible fonts to create your PDFs.

Use Flatten Fat Forms: Flatten fat forms make the form fields unusable and the form data will be merged with the PDF page, which makes your PDF smaller.

Convert to Gray scale: If you don't need colors for your PDFs, you can convert to grayscale, which saves your 54% size of the PDF.

So, what's your best PDF compressor, we are listening and please let us hear you in the comments below.

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1 Comments Leave a Reply

  • Michael

    Same here, got to send PDFs via email but exceeded the limit, this happened very often. Not only make it smaller, also have to make it with better compression quality.

    3 years ago REPLY