I’ve been painting one color for several days–gray: neutral gray, cool gray, warm gray, off-white, and mud.
Lately I’ve used Michael Harding lead white.which is very good and cheaper than Blockx and Old Holland.
I’m well into a cycle of large paintings (large for me, that is). Most of them are into the 4′ x 6′ range. The photo shows two of the unfinished ones.