I just do this in calibre:
VIEW (open the PDF file)
FILE
EXPORT
QUARTZ FILTER (change to BLACK & WHITE)
SAVE
I then take the saved file from
Documents (Macbook Air) and load the file onto calibre and then transfer it to my
Kindle Scribe. Beautiful. The covers are in black and white, but I don't care.
Then (pay attention
), I READ the book as a PDF file.
Most of my PDF files come from Archive.org
WONDERFUL. SIMPLE. ENJOYABLE. PDF FILE. KINDLE SCRIBE. YEAH!