Mixing and Tinting Custom colors can be achieved by intermixing colors or by adding up to 10 ounces of universal or industrial colorant per gallon. The amount of colorant added may affect its performance and extend dry time. To lighten Gel Stain, mix any proportion with Natural Gel Stain. Stir for uniform consistency. Coverage Approximately 1,000 to 1,200 square feet per gallon. If the wood is finely sanded or nonporous, coverage is approximately 800 to 1,600 square feet per gallon. If the surface is porous, coverage is approximately 300 to 500 square feet per gallon. Coverage will vary significantly depending on application method and condition of wood.