PDF is a file format that was designed with one purpose; to ensure a document never lost its formatting when it was read on a different system than the one it originated from and when it was printed. Editing a PDF is almost impossible unless you have the Adobe Acrobat DC, or some such similar app. Most of us have the free Adobe Reader which is very basic in what it lets you do to a PDF file and editing text is definitely not in the feature list. The reader is still equipped with enough features to make for a decent PDF reader so if you’re ever reading at night, or you received a document with a color scheme that makes text hard to read, you can change how the text appears from Adobe Reader’s preferences. Here’s how.
Open a PDF file (any file) in Adobe Reader. Go to Edit>Preferences. In the Preferences window, click the ‘Accessibility’ tab and enable the ‘Replace Document Colors’ option.
Next, select ‘Use High-Contrast Colors’ and select a color scheme from the presets available. If you don’t need a high contrast color scheme but would like to make the document easier to read in low light/at night, select ‘Custom Color’ instead. You can then choose the color of the page, and the document text, and duly invert it so that the page color is black, and the text is white.
The different color scheme renders flawlessly.
The only downside is that this will affect all documents you open in Adobe Reader so you have to change it back when you open a document that’s easier to read, or when you’re reading in better light.