This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
Before priming the painted finish, all knots, sap and strong discolorations must be "killed" with a strong coat of shellac-to prevent any staining, which will occur unless this is done. The painter must be required to examine the finish and report any defects, which must be remedied by the carpenter, and all finish should be gone over with sand-paper before each coat. As to color of the priming coat, white or almost any very light color will do, and it is often well to include in the contract simply this and another finishing coat, as the work will be better done with less opportunity to cover up poor work and less liability of blistering than if three or four coats are applied at once, and a third coat may be applied after two or three seasons to better advantage. An exception should be made in regard to sashes, which should have three or four coats at once. While it is essential that the first coat should be of lead and oil, for the subsequent finish it is not so important. Some of the patent mixed or "chemical" paints are convenient and will last well, especially away from the sea-coasts. Paint should be applied by long strokes parallel to the grain of the wood, and no portion of work should be started in the morning which cannot be finished, or carried to some definite stopping place before night, as the joining of work done at different times will always show a bad place. The back of lattice should be painted and all conductors and metal finish and roofs. Canvas roofs are best treated by dampening and giving a good coat of oil with yellow ochre, then two or three coats of lead and oil paint.
In regard to exterior painting, the use of turpentine is to be avoided, as turpentine does not resist the action of water and so will not preserve work which is exposed to the weather. As oil possesses a natural tendency to discolor white paint, it is customary to mix turpentine with the oil when an absolute white is desired, but in dark colors this is not necessary, and boiled oil only should be used unless a dryer is needed.