All illustrations receive editorial revision before they are sent to the engravers. After they are drawn they are examined with reference to their scientific features and their accuracy, and then in turn with reference to the correctness of geologic names and geographic names and to errors in statement and in spelling. Each illustration thus, before it is completed, receives critical examination by persons qualified in particular kinds of work to detect errors or omissions.
The first proofs of all illustrations are submitted to an author when he is within reach, but if he is in the field and the transmittal of the proofs to him is likely to cause too much delay they are submitted to the chief of the branch or division in which the report was prepared. Second proofs of the more complicated illustrations, particularly geologic maps, may be submitted. An author's examination should be confined principally to the revision of the scientific features of his illustrations, but suggestions as to general effectiveness are always acceptable.
The process to be used in engraving each illustration is stamped in its lower left corner. In examining proofs an author should note the following facts:
1. Changes can not be made in zinc etchings except by eliminating parts, cutting away defects, and connecting lines. If additions are required reengraving is generally necessary, and reengraving should preferably be avoided.
2. Changes can be made in half-tone plates only by re-etching certain parts to make them lighter and by burnishing certain parts to make them darker. If the proof shows a general loss of detail the fault may lie either in the proving of the cut or in the reproduction. If it is in the reproduction it can not be remedied without reengraving. A slight loss of detail may be expected in all half tones, especially in those that are smaller than the copy submitted.
3. Minor changes can be made in photolithographs and chromolithographs, but changes can not be made twice in one place without danger of affecting the printing. It is customary to approve all lithographic proofs subject to the corrections indicated, the printed edition being examined and compared, but if the changes are numerous and radical second proofs may be required. Second combined proofs of chromolithographs are very expensive. (See [p. 89].)
An author should examine the proofs of his illustrations closely and should compare them carefully with the original drawings. A mere cursory examination may fail to detect errors that have not been caught by the regular proof reader. Every correction desired should be clearly indicated with pen and ink in the body of the proof and inclosed in a loop from which a line should be carried to a marginal note or comment, but if the time available is short a pencil may be used. In correcting type matter or lettering (such as that in a geologic legend or explanation) the ordinary proof reader's marks should be used. The author or the person examining the proofs should initial each one at the place indicated by a rubber stamp.