Mounting & Illustration Board
Illustration boards are dense and thick as the paper surface is mounted to a core for stiffness and stability.
Like bristol, illustration boards are preferred by graphic artists and designers - who like how the dense surface accepts marker, pen, and ink. The smoothness of an illustration board also reproduces very well.
Hot Press indicates an ultra smooth and almost reflective surface. Cold Press indicates a slight tooth.
Mounting board is similar to its cousin illustration, but is black through and through, both sides, core, and all.