I visited the Blanton Museum of Art at the University of Texas last week, and was impressed with the current exhibition of works owned by UT alumni and loaned to the gallery.
One of the paintings on display was a portrait by Edouard Vuillard, painted on unprimed cardboard.
I don't usually sketch on toned paper myself, but with some to hand – and with a number of relatives available as models – I used some pencils, including white chalk, to make some family sketches.
There are more on my main website.
(above: cousin Emily, daughter Dorelia, brother-in-law Jon, nephew Toby)