Nikon D5 - Manual (Page 109)

109
If Auto (AUTO) is selected, the color of the lettering in the
information display will automatically change from black to white
or white to black to maintain contrast with the background. To
always use the same color lettering, select Manual and choose
Dark on light (B; black lettering) or Light on dark (W; white
lettering). Monitor brightness will automatically be adjusted for
maximum contrast with the selected text color.
Information Display
G button
➜ B setup menu
Dark on light Light on dark