Supports made of textiles are, compared to wood, flexible and lightweight. The fabric is usually linen or cotton. Traditionally, fabric supports are stretched over stretchers and attached at the edges with tacks or staples. Size Untreated supports, flexible and rigid, are usually too absorbent to permit the uniform application of paint. Therefore, intermediate layers, called size and a ground, are first applied.
Size is a thin solution, often a dilute glue, that is brushed directly onto the support.
The solution permeates the support surface without coating it. It provides a good mechanical bond between the support and the subsequent coatings. Most supports are unevenly absorbent. It is difficult to predict the results of a paint film laid on an unevenly absorbent surface. A ground will ensure a particular kind of paint will perform with reasonable predictability.