The Setasilk Water Based Guttas have a thick consistency and are used to create outlines - the Serti technique. The colors are pearlescent. The Guttas are used directly from the tube and nozzle or from a pipette and Gutta nib. They flow readily into the silk fibers forming a barrier to the color. Setasilk is applied afterwards. All the Guttas can be washed after having been iron fixed with the exception of the colorless Gutta which is designed to wash out leaving a white line on the fabric where it has been applied. Opaque and pearly. Conforms to ASTM D-4236.