In the Fall of 2016, we released a PDF Optimization module with Adobe PDF Library. The goal of this tool was to help our customers reduce the size of their PDF files, improve compatibility and modify PDF files so they are better tailored towards a target audience. Since the release of the tool, we have seen a lot of interest in it, and with that – a lot of great questions. I’ll share some of the more common ones in this blog series, as well as deliberate why and how these discussions are important.
One of the more common requests I have heard lately is “I’m distributing e-books and magazines online, and I need to optimize them.” This is an interesting one. Why would someone need to optimize books and magazines? Aren’t they already optimized when they arrive from the publishers? What we need to take into account is that content comes from many different publishers, using a variety of tools to create it. Each tool adheres to the PDF standard slightly differently, and therefore, each document created is slightly different. Some have high resolution images, different transparency types, too many embedded fonts, not enough embedded fonts, etc. All of this leads to bloated files, and an inconsistent user experience. On top of that, internal workflows might not be able to process the different files coming in. It’s up to the content distributor to ensure that the content delivered to users has a convenient file size, and will display consistently across their devices.
What are some of the major problems plaguing e-books and magazines (and other content distributed online), and how do we solve them?
Transparency comes at the top of our list. Transparencies are great. They let you present rich visual information. However, the transparency specification is fairly complex – over 100 pages. Its interpretation and support varies by different tools. At the end of the day, users are presented different renditions of the same content.
The transparency layers are often not processed correctly by the user’s reading tool. What’s the solution and how can this problem be avoided in content? The answer is to pre-flatten the transparency. This will eliminate all transparencies in a document, and leave only simple to reproduce images. What’s the downside? For some documents, flattening transparencies can slightly increase file size. File size can be reduced, and that’s a small price to pay for a better user experience.
What about images?
Images are a close second when it comes to poor user experience with e-books and magazines. A lot of those documents come with “print-ready” images. This means CMYK color space, spot colors, and also some image alternates in the PDF file itself. A great setup if you are looking to print the file on a professional printing press, but not so great when it comes to a user reading the file on their device. As with transparencies, color interpretation varies between devices, and tools used. Even more so when it comes to spot colors. Interpreting them is difficult, and results can be “spotty”. The best course of action here is to color convert the images in a document to RGB.
To do that, of course, you must use a tool that interprets the colors correctly, or the resulting file will look off. Below you can see the same PDF document reproduced with 2 different PDF libraries. There are multiple issues going on here, but one of them is the color reproduction in the right one is quite off.
This is only scratching the surface of what you can do to improve your content prior to distribution. Look for my future articles on the topic to get more information on what can go wrong, and how to fix it before it happens.
For more information about the benefits of PDF Optimizer, check our our Quick Reference Guide.