Solved. It turns out that when vector graphics from other applications are pasted into any LO program, there’s a setting of the graphic called “Color Mode” that is automatically set to “Default”. This makes a wireframe vector graphic (like an Autocad drawing) which is essentially a black and white graphic, to be treated as a color or grayscale graphic.
Once pasted, on the screen the drawing displays normally. You don’t see any difference, but when you print it on a printer that has no color cartridges (like mine), the drawing appears dimmed. A line that should be solid black is printed as a pale, irregularly dotted, almost imperceptible, gray line.
If you paste the drawing on LO Writer, there is absolutely no way to change the color mode. You are stuck with the dimmed drawing. The solution I have found is to paste the drawing on LO Draw. Fortunately, the Properties sidebar (when you click the drawing) displays a section called “Graphics” in which there is a drop down option that allows to change the color mode from “Default” to “Black and White”.
The modified graphic can then be copied and pasted in LO Writer. And It will print fine.
However, this solution looks like sort of a hack. I’d like to advise the LO developers to include in other applications of the LO suite, besides Draw, the option to change the color mode of embedded graphics. This is really needed to spare your users some frustration and lots of time digging around for a solution to this (I need to repeat here what I stated in the question: this does not occur in MS Word; hence my utter confusion).
In my case, I was lucky to find this workaround. Other people attempting to migrate from MS Office may go the easy way of just saying: “Oops, I can do my stuff in MS Office; I can’t in LibreOffice”. And they would miss all the awesomeness that LO has to offer. Should not happen!
