This section is from the book "Cyclopedia Of Painting", by George D. Armstrong. Also available from Amazon: Cyclopedia of Painting.
Be sure the priming coat is hard dry over the entire surface before commencing to apply the second coat. It is very often the case that part of the work has been primed for a month or six weeks and other portions have stood for only a few days on account of the inability of the carpenter to finish the entire building, or like causes. Places such as the latter will in a short time crack or peel, and when a complaint is entered the entire house is given credit for having been primed a month or six weeks. Do not apply the finishing coat during the time the plasterers are at work, as there is more or less trouble caused by the mortar being splashed or thrown over the work during this time; this necessitates retouching, which cannot be done without showing spots. Do not apply the finishing coat during the time the plaster is drying out, as it will absorb the moisture from the plaster, causing trouble through the paint peeling by having dampness between coats. Finish the interior of the building before applying the exterior finishing coat. This will give time for the plaster to dry out somewhat before this finishing coat is applied and result in a more clean and satisfactory job. See that the basement ventilators are open. This assists in properly drying out the basement.
See that the surface is perfectly clean and free from plaster mortar before starting the work. Carefully putty all nail holes, seams and cracks. Reshellac the knots or sappy places where the pitch may have come through the priming. As this is the finishing coat, exercise care in having the paint uniform and kept to the right consistency to insure proper covering. The paint should be of a full oil reduction so as to be elastic, as this coat must both hide the surface and withstand severe exposure; it must be carefully applied and of the best material in order to accomplish these results. Use a good stock brush and one that has been properly broken in. A new brush will not allow of proper application or spreading of the paint. Work out well under the brush to insure proper binding and a smooth, even coat. Do not use a paint which has to be flowed on to hide the surface, as this will leave a spongy coat without proper binding. Bring the body and trimming color down together. Wipe off the body color from corner strips, door and window frames. Do not work this paint off with a trimming brush, as this will cause spots.
Square up the work at noon and night so as not to have any laps.
See that the surface is dry and in condition to receive paint. Study the character of the lumber and reduce the paint according to its absorbing properties. Note general information in regard to priming new work. The paint should be mixed to a thin consistency to fully satisfy the lumber with only enough pigment used to fill the grain of the wood and not leave an excess of pigment on the surface. This will allow the middle coat to penetrate through the priming coat to a sufficient depth to adhere to the fiber of the wood, as well as the pigment in the primer, thereby assisting in binding itself to the surface as well as to the coats that are applied over it.
If the primer is mixed to a heavy consistency, it will retard absorption or penetration and leave an excess of pigment on the surface that will under contraction and expansion break loose when successive paint coats are applied.