Shrinking PDFs

Recently a friend of mine had an important presentation to make and they wanted to send their presentation to their audience in advance. The problem? The PDF that PowerPoint produced was enormous. Far too large to send via email. They were frustrated. I’ve seen it many times before and there are a few things you can do to ensure your PDFs are of a reasonable size.

One of the first things most people try is making the images themselves smaller by compressing them more. JPG images for example can often be compressed to 30% of their original detail with virtually no loss in quality to the human eye. In modern versions of Adobe Acrobat, this surprisingly doesn’t work and the reason why is interesting.

Acrobat itself has a compression engine. It can reduce the size of a PDF file quite efficiently. And the problem with already compressed JPG files is trying to reduce them doesn’t work that well. Keep in mind I’m talking about compression of quality. Making the image smaller in dimensions does work. And this should always be your first tactic in creating a PDF that you want to keep small: use small images on the page. Full-page and half-page images just take up a lot more space.

Another thing to think about is using images that are easy for Acrobat to compress. PNG images are considered lossless, meaning that image details are not lost when compressing, as opposed to JPGs which are lossy. However, they are extremely efficient at storing uniform areas of colour. So, complex PNGs won’t compress as well, but often the type of images included in PDFs such as graphs, illustrations, etc., have plenty of uniformly coloured areas and hence compress very efficiently. And Acrobat compresses them further.

Sometimes you have the option of using vector images such as Adobe Illustrator files and these are stored as descriptions of images and can be stored extremely efficiently. And they have the benefit of scaling up and down in size without loss of fidelity at all. Almost always the best choice if you can choose it.

If you’ve been provided with the images and don’t have much control over them then the next thing to do is make them as small as you can on the page. Then after saving the file see if you can reduce it further. Again, modern Acrobat has a Reduce File Size built-in which in my experience can often take the file size down to 25 – 30% of the original size. Sometimes more. A creative layout with plenty of white space is generally preferable in many scenarios anyway, so shrink away.

If you’re not using Acrobat there are a few other options. Smallpdf.com will let you upload a PDF up to 5GB in size and reduce it considerably. This is a good option for personal stuff but perhaps not the best choice for business material of a sensitive nature. SmallPDF promises to delete your file within an hour, and privacy is guaranteed, but still...

Adobe.com also has an online tool that lets you optimize your PDF files. Their limit is 2GB but they do have a few more options. The same privacy concerns exist with uploading sensitive documents with Adobe too.

There are also some desktop tools such as Soda PDF which can be found at Sodapdf. com. There is a free version that can be found under the Free Forever area on the home page. You have to create an account, but the free version gets you compression along with some other PDF features.

PDFs have become ubiquitous and are the lingua franca of document exchange in the business world still so it’s worth spending a bit of time learning how to share them easily.
Happy Computing