Sixteenth-century Europeans and early Americans protected their exterior furniture and woodwork -- including barns and fences -- by coating them with a solution of slaked lime and water. When the water evaporated, the lime would react with the air to leave a coating of calcium carbonate, which repelled rot, fungus and insects. Modern whitewashing techniques don't rely on lime and are mostly decorative; whitewashing is a great way to highlight the grain of knotty pine.
First Aid for Knotty Pine
North American designers have a love-hate relationship with knotty pine. Because pine is so abundant -- especially in the east -- early settlers used it for practically all their interior design needs, including furniture, walls and floors. Some designers like to evoke the days of yore with knotty pine paneling and an overabundance of the decorative wood in general, while others prefer to use it in moderation for cabinets and stand-alone furniture. Either way, whitewashing fades the natural yellow tones without hiding the grain, which is the most interesting feature of this softwood. The whitish tones work especially well with Southwest-inspired color themes that include shades of blue combined with oranges and earthy tones.
Use Primer, Stain or Wax
Liming, whitewashing and pickling are all names for the same process, but pickling often calls for grayish colors; whereas, true whitewashing turns furniture white -- the color of lime. It's possible to whitewash the way our forbears did -- by painting a lime solution on the bare wood -- but that isn't necessary, because you can do it with wood stain, white primer or liming wax. It isn't necessary to strip finished wood to use any of these whitewashing materials, but stripping may be a good idea if your pine cabinet or paneling is old and darkened with age.
Whitewashing Unfinished Pine
Whether your pine is unfinished, or you stripped an existing finish, it's a good idea to brush on a coat of wood conditioner after you've sanded the wood and before you apply the whitewashing stain. The conditioner seals the grain with a thin layer of paraffin that prevents blotchiness. If you want to reduce stain penetration even more, seal the wood with clear shellac-based sealer. Use whitewashing stain or dilute white wood primer for the actual whitewashing; brush on a coat and wipe off the excess immediately to leave white highlighting in the more absorbent parts of the grain. Repeat until you get a satisfactory color effect; then coat the wood with clear varnish or lacquer.
Whitewashing Finished Pine
It's possible to whitewash finished wood by using white stain or primer as a glaze. Simply clean the wood with detergent and water and scuff the finish with 220-grit sandpaper; omit the scuffing to increase the subtlety of the whitewashed finish. Brush on the stain and wipe it selectively, allowing more to remain around features you want to emphasize. Liming wax is a whitewashing option that works well on older wood with cracks and defects, because it tends to collect in the open and reinforce the impression of age. Use it to lighten the dull yellow of your older knotty pine cabinets and furniture.