bmp files into the brushtex and papertex folders in your PaintTool SAI files directory. DeviantArt is a website and community with many PaintTool SAI resources. You can download custom brush and paper textures for PaintTool SAI online.How to Install Paper Textures in PaintTool SAI.How to Install Brush Textures in PaintTool SAI.What is Brush and Paper Textures in PaintTool SAI?.