A major advantage of electronic publication is that it costs no more to deliver a color figure online than a black-and-white one. Printing color is, however, still a costly proposition. When publishing each article as soon as it is ready another significant advantage of electronic publication, the placement of the color pages within the subsequent printed version of the journal can no longer be controlled.
For a variety of reasons, articles in the printed version of AGU journals appear in the order in which they were published. Economical reproduction of printed color requires grouping the color in as few signatures as possible. (A signature is a group of 16 or 32 pages that is printed at the same time on a single sheet.)