A web-ready PDF is a PDF file that has been optimised for use on the internet. The size of the file is reduced to make it quick to display on‑screen and quick to download or email.
Adobe developed the Portable Document Format (PDF) file type in the 1990’s as a way of displaying document content, e.g., text, graphics and images, in the same way no matter what hardware or operating system the reader was using. Originally, you had to download Adobe’s own Reader application (or a third-party PDF viewer) to open and display the document but, now that the PDF file format has established itself as a standard, this function is built into all mainstream operating systems and browsers.
When it comes to the web, the end-user’s experience is everything. Nobody wants to wait too long for documents to display, download or email so file size has to be kept as low as possible. But reducing file size affects quality and nobody wants poor quality either so a balance has to be struck. Thankfully, there are techniques that can be used to reduce file size without affecting quality so much that it affects the viewer’s experience negatively. Standard techniques involve optimising how fonts display by embedding only the parts of the font files that are used; how images display by reducing their quality to match the quality of standard computer, tablet and mobile displays and screens; and how the server deals with the file by allowing it to send only the page being viewed instead of sending the whole file in one go. Other techniques can be used to further reduce file size, including stripping out unused or unnecessary features and tweaking the appearance of graphics. Adobe’s InDesign, Illustrator and Photoshop – industry-standard applications used in graphic design – have a built-in export preset for web-ready PDFs named ‘Smallest File Size’ but it’s easy to create a customised set of export rules and save these as a preset of your own if, say, you prefer higher quality images.
So, a web-ready PDF is one that has had its file size reduced so it displays, downloads and emails quickly but not by so much that it negatively affects user experience.
If you want to know about print-ready PDFs, take a look at the next post: ‘What is a print-ready PDF?‘. There’s also a follow-on post which details the primary differences between the two: ‘Web- and print-ready PDFs compared’.