Gimp insists on changing Epson SC-P800 black to photo black on plain paper

I’m trying to print an image on plain paper with an Epson SC-P800 printer using GIMP 2.10 on MacOS 10.14.6 (Mojave). I can find no setting in the print or page-setup dialogs to set which black ink is used. When I attempt to print the printer is prompting me to switch to Photo Black.

Has anyone made this work?