Plastered walls should receive a coat of size before painting. The best size which can be applied to a wall is a thin coat of oil paint. This is hard to apply without showing laps, but these can be easily covered with subsequent coats. When hard dry, apply a coat of warm glue size which will fully stop absorption.
If the walls are to be painted in oil with a full gloss, they should receive the finishing coat of a full oil reduction. If to be half flat, the finishing coat should be mixed to a good consistency with half turpentine and half oil. This will cover the work in a solid manner and make good two coat work.
If a varnish size is used, reduce a fair grade of hard oil finish or varnish to a thin consistency and apply freely with a full brush. When hard dry, apply a first coat mixed with half oil and half turpentine.
If a full gloss is desired, the finishing coat of full oil reduction can be applied over this surface, or, if half flat is wanted, the same mixture as for first coat can be applied, but must be of a heavier consistency.
If the walls are to be finished flat, three coats over a size must be applied. If an oil paint and glue size are used, a second coat mixed half flat will produce a satisfactory foundation for the flat color.
If varnish size is used, apply two coats of half flat paint, the second coat of a heavier consistency than the first coat. If to be left flat, apply one even coat of flat paint mixed to a good consistency.
If to be stippled, the paint should be mixed flat to a heavy consistency, carrying a small percentage of varnish.
In applying a flat color on large rooms, two men should work together in order to avoid showing laps. In stippling large surfaces, it is customary for two men to apply the paint and one man to follow with the stippler.
Where the walls are to be stippled in oil paint, the finishing coat should be mixed to a heavy consistency with 2-3 oil and 1-3 turpentine. Apply the paint medium heavy and allow it to stand a short time, then proceed to stipple. One man can apply the paint as well as do the stippling.
Where walls have been stippled or decorated, they can be protected by applying a thin coat of good starch. Boil the starch and strain. Be sure it is uniform throughout, then reduce to a thin consistency and apply a thin coat and stipple the same as with paint. This will protect the decoration, and after it becomes soiled with smoke it can be washed off and another coat of starch be applied in the same manner as before, thus saving the decoration for an indefinite length of time.