A number of people have asked me how I create my custom sanded papers. Well, this is the process that I follow. I hope it helps you
Collect Clear Gesso
Pumice Stone FF
Fluid Acrylic for Tinting
Mix equal parts gesso and pumic
Add desired tinting
Add water in very small amounts if it needs thining
Use a good sized brush to spread the gesso mixture.
This can be applied to foam board, gater board, mat boards
and in my case I'm currently applying this gesso mixture onto 300 lb print paper.
I painted two coatings in order to get a solid coat