The black was made from a mineral that was mined in Colorado. It was cheap, dried fast and held up well.
In 1926 the open cars were still black but the closed cars were other colors unless you ordered them in black to match the black cars your company already had in a fleet.
I am quite sure my ‘26 touring came in black.
Late in ‘25 there was a great improvement in the quality of paint, mainly it dried faster.
That was when Ford started using other colors again. People were sick of black and often bought other makes just for the nice colors.