I am painting the space between the circles with a thinned-down mix of Graphite Grey and Mars Black (also called Iron Oxide Black). Mars Black is a heavily granulating pigment and creates a very interesting texture.
Some oil paint is transparent and quite dark straight from the tube, so I need to add white to it. For this I use Tinting white because it does not overpower the color and make it look chalky like Titanium white can do.
I may still decide to rework some smaller areas, but the most work is definitely done. Now it has to dry a few months and then it will get a varnish and a frame. And hopefully I find someone who wants to have it because I got no space for it 😅