Are you looking to darken the PDF for reading in dimly lighted areas? If yes, you can find PDF reader that have a dark reading mode or a accessibility feature that will allow you to change the view to make it darker. Foxit PDF Mobile has the dark reading mode feature and Foxit PhatomPDF for Windows has the feature located in File->Preference->Accessibility -> Replace document colors. If you want to make it darker in general, that might be a harder task. PDF are made of many objects and you cannot easily darken all of the object at once. Typically you would need to darken each one by one.
What To Do In the Next Step? The task would be to install the Adobe Reader to get access to the dark mode for reading PDF documents. If you are new from web development with no previous experience with PDF, check out this great guide on Learn Code with WordPress In case you are already familiar with PDF, let me recommend the following resources in the link below: If you have a better idea how to handle it, leave a comment, and I'll be glad to answer. Don't forget to try it yourself and feel free to share your opinions and experiences in the comment section below. Like Share You and 55 others like this. 55 people like this.