Posted by dellus on Feb 26, 2016; 1:49pm
URL: https://forum.librecad.org/Adjusting-the-printer-to-print-dark-lines-in-LibreCad-drawings-tp5712550p5713091.html

Ok, what bothers Mike may really be a minimum linewidth in pixels on screen problem. As far as I know Librecad behaves the same as other cad-programs in this respect. This may be an issue with modern high resolution screens especially.
It might help to try out a different background colour.