working the surface: stone dust, acrylic on stretched canvas

this is a detail of a metre square and a preparation for drawing (snapse#2)
The process is an extention of the coal dust exploration but here using the oamaru stone dust, sieved super fine, mixed with acrylic white and when dry sanded back with wet/dry. The surface is stunning really, marble like, hard and tight. It also remains a little transparent. this image shows the effect having applied india ink, stone dust and sanded back to the colour.
I've since applied more colour and more stone dust...eventually when this settles I plan to do more non figurative drawing on this support!