The weight, structure and surface finish of a fabric have an influence in pressing in addition to the actual fiber content already mentioned. Lightweight fabrics require additional care because whatever sensitivity the fiber itself may possess is intensified by fine yarns and fine structure. Crepe fabric i.e. true crepe fabrics made from hard twisted yarn, require very careful pressing treatment with a minimum of moisture to prevent excessive shrinkage. The neatening effect of pressing does not always involve the flattening of a fabric surface. In the case of certain nap fabrics and in all pile fabrics flattening are undesirable. This can be avoided by pressing the reverse side lightly on a very soft surface or by the use of a needle board, i.e. a pad with a surface composed of wire points closely set together which allows the pile fabric to remain upright while the back of the fabric is pressed. Fabrics with a rough on an embossed surface also require light careful treatment on the reverse side on a soft surface to prevent undue surface flattening or glazing. Where it is essential for pressing to take place on the right side of a fabric, great care must be taken to avoid producing glaze or luster where not required. The use of moisture is help in this respect, except in acrylic fibers, and the surface of a pile fabric will often respond to the use of steam along without any pressure.