So a year or so ago, I learned a little tip on an install at work. I’m not sure how known this is, but thought I would pass it along.
We were installing a signage system for HSBC bank and had to paint an orange square behind everything. We taped the box off, and were told to put some matte white paint down first to prevent bleed-through at the edges. We brushed on some white at the tape line, then painted the orange, and had crisp, straight lines when we peeled off the tape.
I recently painted the inside of some drawers on a desk I’m working on, and wanted to keep the end-grain of my multi-ply free of paint. So I put down blue tape and used a razor blade to shave of the overhang close to the edge.
Now, when I began thinking about this whole “paint the tape line first” thing, I realized you just put down a base coat that you will never see to close any open gaps between the tape and the wall (in this case, drawer). We were told to use matte white, because that was the color of the wall. Since I was planning on a clear laquer, I went out and bought a small can of MinWax Clear Satin Acrylic Poly. I choose this because of the fast drying time, though really anything clear, such as shellac or laquer, would have worked.
I brushed on a decent layer of clear at the tape line, let it dry, then brushed on the color. After all of my coats were dry, I removed the tape, and the edge turned out clean, with paint only where I wanted it. A little bit of the MinWax bled through, but since I would be laquering it, I was not at all concerned.
I believe that this tip only really applies to paint though, as stain would end up bleeding through the grain under the tape, and won’t penetrate whatever you use as a basecoat. But if you ever end up painting something, be it drawers or stripes on a wall, just match your basecoat on the tape with the finished color you are painting on top of.
Sometimes having a job you hate ends up helping you out!
-- -Shaun M. Baer, http://www.craftedphiladelphia.com