There are two sizes associated with each psfig figure: the size at which it is to be printed on the page and the size it reserves in TeX. This latter size is appropriately termed the reserved size, and is expressed as clauses of the form `` rheight= dimen'' and `` rwidth= dimen''. If omitted, the reserved size defaults to the real size. Some special effects need to be transparent to TeX and thus have a zero reserved size, such as the grey box enclosing this paragraph.