Nope, not contrast paint. The medusa miniature was a mixture of wet blends and ink washing/drybrushing. The cloth is a craft paint base layer then a thin mixture of paint/Windsor&Newton ink over the top. I added highlights over the wash. W&N ink is not waterproof so it reactivates and you get smooth blends of colour.
The Bedsheet Ghost was a wash of Daley-Rowney 'paynes grey' acrylic ink then several layers of highlights.
I have some contrast paints but I haven't really found a use for them yet!