If you need more liquid, add a little more beet juice or water to reach desired depth. (epicurious.com)
Repeat until desired depth of color is achieved, lightly sanding with fine steel wool between coats and after final coat. (cececaldwells.com)
Once at the desired depth waves were generated at varied frequenices until the supperadiant scattering effect is created and recorded using a specially designed 3D air fluid interface sensor. (sciencedaily.com)