Based on the colour wheel by Johannes Itten I modified the colours by increasing the transparency and the amount of black.
Different combinations by layering two colours revealed lots of well-paired colour shades. Also thought about different textures. Different layers of colours trough soft textures like clouds, fabric,...
Josef Albers was a German - born American artist who did lots of studies of colour. Trough the transparenz of colour he created new shades of colours. (last picture)