Making images with 300 dpi

[rich2005]

Your book 8" x 10"  @ 300 ppi = 2400 x 3000 pix  How much for margins ? say 0.5 " all round gives a working size 7" x 9" @ 300 ppi = 2100 x 2700 pix.

So you would make your canvas (a template)  in Gimp 2400 x 3000 with a resolution of 300 ppi. Put in some guides for margins/bleeds. Anything you add to that  takes the 300 ppi setting.

So set the export in LibreCAD  to something that fits in 2100 x 2700 **Look* at the screenshot in post #3 **Change** the size.
jpeg is a poor format for export your smaller image as a png is not a monster file size.

Import the file made by LibreCAD File -> Open as layers  Even if you need to a little scaling to fit, the base image is 300 ppi and that is what you will get when you finally come to export.

The 96 ppi output from LibreCAD is common for vector appications, Inkscape is the same. A vector can scale up or down without quality loss **until** you render it to a bitmap.

Edit:

Here is an example: https://youtu.be/xW3f9yMadHE  2' 30'' - no audio