The Preparation of Illustrations for Reports of the United States Geological Survey With Brief Descriptions of Processes of Reproduction

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DEPARTMENT OF THE INTERIOR.

John Barton Payne, Secretary

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United States Geological Survey

George Otis Smith, Director

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THE

PREPARATION OF ILLUSTRATIONS

FOR REPORTS OF THE

UNITED STATES GEOLOGICAL SURVEY

WITH BRIEF DESCRIPTIONS OF PROCESSES
OF REPRODUCTION

BY

JOHN L. RIDGWAY

WASHINGTON

GOVERNMENT PRINTING OFFICE

1920

CONTENTS.

Page. Part I. Preparation by Authors. Introduction 7 Purpose and value of illustrations 8 Selection and approval of illustrations 8 Submittal of illustrations 10 Kinds of illustrations 10 Sizes of illustrations 11 Subdivisions of plates and figures 12 Preparation of copy by authors 12 Character of original material 12 Preliminary preparation of maps 13 Material available for base maps 14 Basic features of maps 17 Standard scales 18 Orientation of maps 18 Projection 18 Explanation 19 Titles of maps and other illustrations 19 Symbols used on maps 20 General features 20 Letter symbols 20 Oil and gas symbols 21 Symbols for use on maps showing features of ground water 21 Black-line conventions 23 Materials used in preparing maps 23 Paper 23 Bristol board

tag="{http://www.w3.org/1999/xhtml}a">24 Tracing linen 24 Inks 25 Drawing pens 25 Pencils 25 Rubber erasers and cleaners 25 Colored pencils and crayons 26 Water colors 26 Japanese transparent water colors 26 Coloring geologic maps 27 Diagrams 28 Essential features 28 Plans of mine workings 29 Sections 29 Lithologic symbols 32 Use of photographs as illustrations 32 Essential features 32 Copyrighted photographs 33 Sources of photographs 34 Lending original photographs and drawings 34 Unpublished photographs 34 Specimens 34 General requirements 34 Borrowed and fragile specimens 35 Transmittal of paleontologic specimens 35 Making up plates 36 Reuse of illustrations 37 Approval of finished illustrations 38 Revision of illustrations 38 Submittal of proofs 38 Proof-reading illustrations 39 General considerations 39   Part II. Preparation by Draftsmen. General directions 41

class="ind1">Instruments 42 Classification of material 42 Preparation of maps 43 Projection 43 Details of base maps 45 Transferring or copying 46 Tracing 46 Celluloid transferring 47 Sketching by reticulation 47 The "shadowless drafting table" 47 Topographic features 48 Relief 48 Hydrography 51 Cultural features 52 Lettering 53 General directions 53 Lettering by type 54 Abbreviations 55 Names of railroads 57 Make-up of maps 57 Forms for certain features 57 Border 57 Title 58 Explanation 58 Graphic scales for maps 59 Symbols 61 Areal patterns for black and white maps 61 Standard colors for geologic maps 63 Reduction or enlargement of maps 63 Diagrams 64 Sections 64 Plans and cross sections of mines 65 Drawings of specimens of rocks and fossils 66 Methods

used 66 Brush and pencil drawings 66 Pen drawings 67 Retouching photographs of specimens 68 Landscape drawings from poor photographs 68 Pen drawings made over photographs 68 Brush drawings from poor photographs 69 Outdoor sketches 69 Drawings of crystals 70 Retouching photographs 70   Part III. Processes of Reproducing Illustrations. Methods employed 72 Photoengraving 72 General features 72 Zinc etching 73 Copper etching in relief 75 Half-tone engraving 75 Three-color half-tone process 78 Wax engraving (the cerotype process) 80 Wood engraving 81 Photogelatin processes 82 Lithography 83 Original process 83 Photolithography 86 Offset printing 87 Chromolithography 87 Engraving on stone and on copper 89   Appendix. Length of degrees of latitude and longitude 91 Metric system and equivalents 92 Geologic eras, periods, systems, epochs, and series 92 Chemical elements and symbols 93 Greek alphabet 93 Roman numerals 93 Mathematical signs

href="@public@vhost@g@gutenberg@html@files@43232@[email protected]#Page_94" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">94 Names of rocks 94

ILLUSTRATIONS.

Page. Plate I. Methods of inserting plates and figures 10 II. Symbols used on geologic maps, economic maps, and mine plans 20 III. Lithologic symbols used in structure and columnar sections to represent different kinds of rock 32 IV. Symbols used on base maps 52 V. Reduction sheet used in lettering illustrations 54 VI. Half-tone prints showing effects produced by the use of six standard screens 56 VII. Details of the make-up of a geologic map 58 VIII. Patterns used to show distinctions between areas on black and white maps 60 IX. Diagrams and curves 64   Figure 1. Diagrams showing principal, guide, and auxiliary meridians, standard and special parallels and correction lines, and system of numbering townships, ranges, and sections 16 2. Conventional lines used in preparing plans and diagrams of mine workings to distinguish different levels 29 3. Section and perspective view showing relations of surface features to the different kinds of rocks and the structure of the beds 30 4. Sections of coal beds 31 5. Diagram illustrating method of projecting a map 44 6. Methods of expressing relief by contour lines, by hachures, by shading on stipple board, and by a brush drawing 49 7. Designs for bar scales 60 8. Method of making a bar scale for a map of unknown scale 60 9. Map bearing six areal line patterns 62 10. Diagram showing method of marking maps for reduction or enlargement (for record) 64 11. Structure section showing method of determining the succession of folds 65

THE PREPARATION OF ILLUSTRATIONS FOR REPORTS OF THE United STATES GEOLOGICAL SURVEY.

By John L. Ridgway.

Part I. Preparation By Authors.

INTRODUCTION.

There has been an obvious need in the Geological Survey of a paper devoted wholly to illustrations. No complete paper on the character, use, and mode of preparation of illustrations has been published by the Survey, though brief suggestions concerning certain features of their use have been printed in connection with other suggestions pertaining to publications. The present paper includes matter which it is hoped will be of service to authors in their work of making up original drafts of illustrations and to draftsmen who are using these originals in preparing more finished drawings, but it is not a technical treatise on drafting.

The effectiveness of illustrations does not depend entirely on good drawings nor on good reproduction; it may be due in large part to the inherent character of the rough material submitted. If this material is effective or striking the finished illustrations, if well made, will be equally effective and striking. Each step in the making of an illustration—first the preparation of the author's original or rough draft, next the final drawing, and last the reproduction—is closely related to the others, and each is dependent on the others for good results. If the material has been well handled at all three steps the resulting illustration should be above criticism; if it has been poorly handled at any one of the three the effectiveness of the illustration is either impaired or ruined.

A consideration of processes of reproduction is essential in the preparation of all illustrations, and the influence or effect of the process to be selected on the methods of preparing a drawing has seemed to warrant the presentation of brief descriptions of the processes usually employed by the Geological Survey. These descriptions include statements as to the kind of copy that is suitable for each process, the result produced by each, and the relative cost of the processes.

PURPOSE AND VALUE OF ILLUSTRATIONS.

An illustration in a report of the Geological Survey is not merely a picture having a remote bearing on the subject matter of the report; it must represent or explain something discussed or mentioned in order to become an illustration in the true sense of the term. The illustrations used in the Survey's reports are not employed for embellishment; the more pictorial kinds may be in some measure decorative, but decoration is distinctly not their primary purpose. The illustrations used in popular literature are designed to meet a public demand for ornament or attractiveness. Those used in scientific

publications should be made plain and direct, without attempt to ornament or beautify. In the literature of science illustrations made by the reproduction of photographs or of explanatory diagrams or maps are intended simply to furnish greater illumination, and if the illustrations display photographic reality most statements or conclusions thus illuminated seem less open to dispute. A photograph may thus serve the double purpose of explanation and corroboration. The graphic expression of data and of details in a Survey report is intended to aid the reader in comprehending the report, and this is the prime advantage of its use, but it also enables the writer to omit from his text numerous descriptive details. It would generally be difficult without illustrations to present a clear picture of the geology of a region in its exact relations, and especially to describe adequately the form and the details of the structure of many fossils. The tasks of both the writer and the reader of reports on geology and kindred subjects are thus greatly facilitated by geologic maps, sections, paleontologic drawings, and illustrations of other kinds.

The responsibility for good and effective illustrations rests largely upon the author, who should select and plan his illustrations with a view to their utility in aiding the reader to understand his report.

SELECTION AND APPROVAL OF ILLUSTRATIONS.

There is no rule limiting the number of illustrations that may be used in a publication of the Geological Survey, but in selecting illustrations for a report an author may easily fall into the error of over-illustration. The number of diagrammatic drawings or of drawings that express the author's deductions is rarely in excess of the needs of a paper, but the number of photographs submitted is often excessive. The number of pages in a manuscript may be a factor in determining the proper number of illustrations, but as the need of illustrations varies greatly from paper to paper this factor alone is not decisive. The tendency to overillustrate led the Director to issue the following order[1] governing the approval of illustrations:

The judgment of an author as to the illustrative value of a photograph is likely to be biased by his knowledge of the features that are actually included in the view represented, not all of which may be shown clearly in the photograph; his knowledge of all the features enables him to see more in his picture than his readers will be able to recognize without detailed description. Photographs in which special or significant features are obscured by foliage or lost in hazy distance do not make acceptable illustrations, and the use of a picture that requires much description to make it illustrate reverses, in a measure, the relations of text and illustrations.

A photograph is not necessarily good for reproduction simply because it shows some particular feature to be illustrated; the quality of the print it will afford when reproduced from an engraved plate should also be considered. Some loss of detail by reproduction must be expected, and therefore only the clearest and most effective prints obtainable should be submitted.

If an author has difficulty in making his preliminary or "original" drawings he may request that a draftsman be detailed to aid him. The request should be made to the Director through the chief of branch and properly approved. The work will then be done in the section of illustrations as advance preparation, but finished drawings should not be thus prepared unless the conditions are unusual. The administrative geologist reviews all illustrations submitted and represents the Director in matters relating to illustrations.

SUBMITTAL OF ILLUSTRATIONS.

All material intended for illustrations, except paleontologic specimens, should be submitted with the manuscript of the paper to be illustrated but in a separate package marked "Illustrations to accompany a paper on —— by ——." The package should contain a carbon copy of the list of illustrations that accompanies the manuscript or, if the titles to be printed on or with the illustrations include fuller descriptions than are given in that list, a carbon copy of the list giving complete titles and descriptions, the original of which should also accompany the manuscript. In the list each plate and figure should be separately numbered consecutively in the order in which it should appear in the report, and a figure opposite each title should show the number of the manuscript page on which the illustration is first mentioned or most fully discussed. Roman numerals should be used for the plates and arabic numerals for the figures. Each drawing or photograph should bear, in addition to the number and title, any suggestions concerning preparation, reduction, and method of reproduction which the author may consider especially desirable. The list should be headed "Illustrations."

Specimens other than fossils that are to be illustrated must be submitted directly to the section of illustrations, but the author may first obtain photographic prints of them in order to make up his plates. The specimens should be carefully packed and any that are fragile should be so marked.

KINDS OF ILLUSTRATIONS.

The illustrations in reports of the Geological Survey may be classified into five more or less distinct groups—(1) maps, (2) diagrams (including graphs, sections, plans, figures of apparatus, and stereograms), (3) outdoor photographs, (4) photographs and drawings of specimens, and (5) sketches. These may be further divided into two large groups, which may be called permanent and ephemeral. The permanent group includes illustrations that do not lose value through lapse of time or by natural alteration, such as detailed geologic maps, well-prepared structure sections, views of specimens, and good photographs or drawings of natural phenomena; the ephemeral group includes maps showing progress, key maps, diagrams showing yearly production, and many others that should be prepared in such a way as to minimize cost of preparation and reproduction.