Posted by dellus on Feb 26, 2016; 12:40am
URL: https://forum.librecad.org/Adjusting-the-printer-to-print-dark-lines-in-LibreCad-drawings-tp5712550p5713084.html

Having the line width a real world representation makes sense with drawings of relatively small objects, like mechanical parts expected to be printed in a scale of 1:1. With large objects, let's say a wall 10m long, a line width of 0.5 mm pen size appears thin as a hair at 1:1. Imagine it drawn on the floor. But if scaled at 1:100 and still applying 0.5 mm pen width it appears thick, a solid wall.
I don't think you can handle this satisfyingly with a pixel value, as this doesn't change when zooming in and out.
More advanced commercial cad programs show the line width according to certain scale, like LC in the print preview. You then need to have a scale setting option in the drawing view also.