You will need 2 parts water to 1 part paint ratio. So for instance, I used 1 cup of paint and 2 cups water. Mix well with your paint brush. Next, paint your boards, doing only small amounts at a time. Before the paint has dried, use your towel to lightly wipe off small amounts of the paint, wiping with the grain of the wood.
DIY BARN WOOD :: She stained a piece of scrap board with Minwax white tint base wood stain in Slate and realized it was a bit too dark for her liking so she mixed the stain 50/50 with water which made a big difference. She let it dry over night and the next day used some ASCP in Pure White to white wash over the wood (mixing 1-2 Tbsp. with 1 cup water). She brushed it on then wiped it off with a paper towel. :: CLICK or here's another link: www.hawthorneandmain.com/2014/09/diy-barn-wood.html