I have painted on a very sturdy double-sheet (two sheets on top of each other glued by gesso - so that it is a substantial material; more like a board than paper) of Hahnemuele mould-made, acid free, age resistant paper (450 g/square meter, 210lbs) using artists quality acrylic paints. The painting is varnished to protect it from airborne pollutants and UV damage.
The colours I've used in the painting are around "fifty" shades of blue, some yellow and white, and one shade of gold (the diagonal strike - in the photograph the gold shade is not very well recognizable).
The painting is mounted, and its mounted dimensions are 40 x 30 cm (15.75 x 11.81 inch), so that it would fit in regular frames of the size 40 x 30 cm.
The painting comes with my certificate of authenticity.
Hahnemuehle double page of sturdy, heavy paper, acrylics, shades of blue, gold, white, varnish