Posted by dellus on
URL: https://forum.librecad.org/Printing-issue-tp5724798p5724805.html

APPLY PRINT SCALE TO LINE WIDTH compares the scale the drawing was originally intended for and the scale chosen in Print Preview. So if original scale was 1:100 and now you want a miniature print in 1:200 then line widths are the half. The information for the originally intended drawing scale is taken from Option - Current Drawing Preferences - General Scale. Here you have 0.1, that's why you get the faint lines.
See here what is behind "General Scale":  
https://docs.librecad.org/en/2.2.0_a/guides/annotate.html#adjust-dim