According to J.T. Marsh, in An Introduction to Textile Finishing (1951) calendering "is an important branch of the finishing of cotton, linen, rayon, and silk material..."

"The chief essentials in calendering are the moisture present in the cloth at the moment of calendering, the composition, number, and arrangement of the bowls, together with their pressure and temperature. The bowls may be made of metal or of compressed material such as cotton or paper; the degree of hardness depends on the particular finish for which the bowl is intended. The metal bowls are usually made of chilled iron with a hard, highly-polished surface; these bowls are generally hollow, so that they may be heated, but very often the bottom bowls are made of close-grained cast iron..." "Calenders are made in many different forms, with from two to eleven bowls, and may be adapted to perform various finishing operations; some of the larger calenders are fitted with the necessary devices for utilising only a certain number of the available bowls..."

"Friction calendering, however, gives a higher gloss and a greater closing of the yarns; it is produced by bringing the cloth into contact with a heated, polished, chilled-iron bowl which is travelling at a faster speed than the cloth itself...."

I believe that in this case, "bowl" could be translated as roller.

During the hard press, I use a very heavy iron (when I can - I'm looking for an old fashioned steam/boiler tailor's iron weighing in at about 5 to 7 pounds if anyone knows of one I can buy) and press directly onto the cloth. No I don't use a pressing cloth. Yes, I do stroke the iron across the cloth (depending on the type of cloth and what needs to be done to appropriately flatten it). If I don't want the resulting sheen on a wool fabric, a simple steaming will remove it.

For one of the samples for the Guild of Canadian Weavers newsletter, I rolled the fabric around a large pvc pipe, then sat on it and rocked back and forth to flatten it. I still had to give it a hard steam press to get it sufficiently flattened to be used for sewing a garment.

In Sweden, I saw the "old fashioned" mangles which were basically a large dowel (3"?) and a flat board with a handle. The fabric is rolled around the dowel, and the flat board is pressed down onto the dowel with cloth. With a rocking motion, you roll the dowel back and forth under pressure. This is actual quite effective for smaller pieces.

Mangling isn't the same as calendering, but more accessible for handweavers to accomplish than actual calendering. For a more detailed explanation of mangling, please see the article &qupt;Mangling" by Kerstin Froberg in this section.