Black paint and 1/72 scale

What are you useing it on, is it for tires or somthing else.

French Vautour IIn  instructions say cockpit is black.

In that case, i would go with black and then dry brush with black lightened with a dark grey.

I usually lighten any flat black that is supposed to be a painted surface or a black material. I leave unadulterated flat black for representing cavities that I do not want to open into real cavities.

For gloss blacks, I do use it straight.

The amount to lighten the flat black is not really critical- any lightening helps. Surfaces on top of model chalk from sunshine, so these should have more lightening than blacks on the side of a vehicle.  And blacks down low- tires, chassis, etc. can get dusty easily. I tend to lighten these with a tan rather than a gray.

polyscale used to have a scale black. for small parts (not entire hulls) i use MMA engine gray. there are so many other variables as well such as the type of lighting iy will sit in, how intense the lighting is surfaces and paint nearby. i usually weather with powders in the sulight when possible.