Joints will create an interesting texture with sunlight, making shadow- effects that form a constantly changing and ever-fascinating pattern on the wall. Various textural effects can be obtained by the way in which the joints are shaped-by raking out the joints to get an indented shadow, or by squashing out the mortar in the joints and then either leaving them as an informal, irregular mass or shaping them so that they are extruded but formal. Even the color of the mortar can influence the final result. For instance, mortar which is dark in color will cut down the shadow effect on medium- to dark-colored walls. Conversely, white or light-colored walls with darkened mortar forming the joints will produce a far stronger pattern than if pale or white mortar is used. Dark masonry units with light-colored mortar will also have an impact because of the contrast of color. And all this is quite aside from the three- dimensional patterning caused by raking or otherwise shaping the mortar joints.

Where walls face the sun a good part of the day, more shadow texture will be apparent than on walls which receive only light reflected from the sky or from other buildings, as on north-facing walls. Hence, if it is desired to emphasize texture on northern walls the raking should be a little deeper, the shaping intensified, in order to obtain the proper pint shadows.

Sometimes, particularly where a very formal or refined sort of masonry work is used in modern or fine traditional architecture, it is attractive to have no joints showing at all or to subordinate the joints to the texture of the masonry units themselves. In that case, a flush joint is the answer. You may even tint the mortar to approximate the masonry unit color if you wish to pursue the flat effect to its final conclusion. Thus, by using flush joints with mortar in a related color, a very subtle textural effect with a subdued pattern is produced to make a unique architectural contribution to the general picture.