I ordered some Sennelier Pastel Card and it arrived today.
It is very different to Clairefontaine Pastelmat, which has the texture of velvet. This Sennelier card is like a fine grit sandpaper, which has both disadvantages and advantages. It holds A LOT of pastel but because it is so rough, tends to make the pastels crumble, something I’ve never experienced with Pastelmat.
Anycase, for my test piece I did this:
I used the dark green toned Pastel Card and it is 24x32cm or 9.5 x 12.5 inches