From a reader:
Some churches in my diocese have recently begun the practice of having no altar cloth. I.e., only when Mass is said is there a small cloth unfolded on the altar beneath the paten and chalice — otherwise the table altar is bare. Is this permitted under Church law or whatever governs such things?
What you describe has nothing to do with our Roman tradition. Moreover, I refer you to the General Instruction of the Roman Missal.
GIRM 304. Out of reverence for the celebration of the memorial of the Lord and for the banquet in which the Body and Blood of the Lord are offered, there should be, on an altar where this is celebrated, at least one cloth, white in color, whose shape, size, and decoration are in keeping with the altar’s structure. When, in the Dioceses of the United States of America, other cloths are used in addition to the altar cloth, then those cloths may be of other colors possessing Christian honorific or festive significance according to longstanding local usage, provided that the uppermost cloth covering the mensa (i.e., the altar cloth itself) is always white in color.
Thus, it is not enough just to put a corporal on a bare altar. There should be at least one altar cloth.
Traditionally, we Romans use three cloths on our altars.