[luatex] Change background color for Plain TeX using LuaTeX?

[Steve Litt]

This regards Plain TeX. I know there are ways to easily do it in
LaTeX.

Is there something I can put within \directlua{} or anywhere else
to change the background color of a series of letters or a series of
lines?

Thanks,

SteveT

Steve Litt
November 2018 featured book: Manager's Guide to Technical
Troubleshooting Brand new, second edition
http://www.troubleshooters.com/mgr