This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
192. Face brick are usually laid in mortar made of lime putty and very fine sand; often the mortar is stained with mineral pigments to match the. color of the brick. The joints should not exceed 3/16 of an inch in thickness, and, for very fine work, they are sometimes kept down to 1/8 of an inch. The joints should be completely filled with mortar, and either finished at once or raked out for pointing. In very particular work, such as laying pressed and enameled brick, a straightedge is held under the joint and a jointer run along on top of it, thus making a perfectly straight joint. This is called ruled work. Many masons prefer using a trowel.