There’s no question that a picture is worth a thousand words. In fact, studies show that 40 percent of people will respond better to visual information than they will to plain text. This is likely because 90 percent of the information that comes to the brain is visual. That’s why using illustrations, photographs and other images greatly enhances the context of your PDF document. Using images gives a visual representation to your text. In technical documents, images make it easier for the reader to follow and comprehend directions and explanations.
There is, however, a difference between simply adding an image into a PDF document and making sure that the image is set up properly. Optimizing image files aids with accessibility, clarity and the overall size of your PDF document so it’s an important consideration. Yet as important as optimization is, it’s not a difficult process. Here are some best practices for optimizing images in your PDF files.
Optimize for accessibility
Accessibility ensures that anyone can read your document without limitation. For people who are visually impaired, PDF software allows you to include alternate text descriptions for images that you include in your document. This allows any text to speech or read out loud tools to describe what the image is. Visually impaired readers don’t miss out on the enhancements your images provide to the content.
Accessibility also affects people who speak languages other than the one used in the original document. Images that contain words and descriptions in them can cause problems when translating document into other languages, as translators don’t usually change image text. If the content contained therein is important, its meaning is lost on some. To ensure that you leave no one out, images should not contain any text if possible. Instead, use captions or reference the image in the content itself.
For more tips on creating accessible PDFs, see this article.
Provide clarity in images
If readers have trouble making out the image, its effect can be lost. That’s why it’s a good idea to use images with enough resolution so that readers are able to see things clearly.
Larger graphics also present a problem for some documents. If too much is conveyed in one image, readers might find the graphic to be more confusing than helpful. Optimizing graphic images for clarity means that the image should only convey what you describe in the text. This not only helps the reader understand your content more clearly, it also keeps the image to a manageable size.
Optimize file size
Including images in a PDF document will increase the size of the overall file significantly. This can cause problems when delivering documents via email or uploaded through a file transfer, as there are usually file size restrictions in these environments. You can easily manage the impact that images have on file size.
Using the right file type is important. Images saved in .jpeg format often have the best clarity since you generally use this format for photographic images. The result is that .jpeg files are also larger. On the other end of the spectrum, the .gif file format is smaller in size, but you lose sharpness. As a result, consider opting for the middle ground found with .png files. These keep a higher level of sharpness and clarity, while keeping the file size much lower than that of a .jpeg.
So as you—and recipients of your PDF documents—can see, optimizing graphics and images for PDF not only makes good sense, it’s easy to implement as well.