PDF To Word In Seconds. · For All Devices · Make PDF Files Editable. · User-Friendly InterfaceServices: PDF Editor, PDF To Word, PDF To Excel, PDF To JPG, PDF To PNG, PDF To EPUB. Here’s how to darken text in PDF files and make them readable. Method 1: Adjusting Contrast in PDF Files One of the most straightforward methods to darken the text is to adjust the contrast .