Unclear display of scanned pages

Problem/Motivation

After installation and configuration on the local server, the display of scanned documents is poor.

Steps to reproduce

Installed the module and libraries.
Created a field with the type "file"
У In the display options, select "PDF Reader"
In the settings, select the Renderer "Pdf.js"
Created content with the file.

Pages of the file that are scanned are displayed poorly
I have no idea why it will be displayed like this.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes