Floyd 0. slate1 Cornell University lthoco, New York
Photographs for Technical Reports
The purpose of this paper is to discuss the use of photographs in technical reports, both written and oral-to discuss their realm of application, their advantages and disadvantages, their limitations, and some details of their use and preparation. The scope of the paper is limit,ed to general points of discussion; no attempt is made to cover this large field comprehensively. The illustrations used are ones that have actually been used t,o illustrate technical reports, mostly as slides for oral reports. They represent a reasonable cross section of photographs in general use and will be used to illustrate both good and bad usage of the photographic technique. There can be no doubt that photography is-or can be-a po~~erful tool for the communication of technical information ; there can also be no doubt that it is seldom wed to best advantage. Few writers use enough photographs, but many i f these few promiscuously bviruse them. The average writer cannot be expected to be an expert photographer, hut he can be expected to know when an illustration is needed and what type of illustration is appropriate. He should know when the photographic technique is called for, how to pose or arrange the subject if possible, and how to judge the merits of a given photograph for inclusion in his report.
of a metal, as brought out by etching; the surface characteristics of smoke and clay particles, as shown by the electron microscope; X-ray diffraction patterns-these things can be reported successfully only by means of photographs. The field geologist must rely heavily upon the camera to record his observations; the botanist, unless he be a Leonardo da Vinci, must depend upon the camera to record his subjects faithfully. In like manner, all technical men will find cases where they cannot force words to convey a mental picture adequately to their readers or listeners, but where a photograph will accomplish this end simply. An example of the use of photomicrography is shown by Figure 1. The use of this technique presents especially difficult problemsinlighting and focusing. Magnification should be stated on all photomicrographs, preferably by a scale marker in the field. The method of
Unique Advantages of Photographs In general, photographs are used to express ideas beyond the power of words and to illustrate or enlarge upon ideas and concepts that are expressed by words. A limited number of carefully chosen, high quality photographs can often present clearly and attractively a type of information that cannot be transmitted by an infinite number of words. In cost of publication, words are much cheaper; this fact may require severe cutting of illustrations in profusely illustrated manuscripts. Typical cases where only photographs can adequately describe an idea are: the damage to a bombed-out city, the ravages of a disease, the appearance of a newly discovered biological specimen (imagine your embarrassment in trying to describe precisely the appearance of a platypus), t,he effect of damage on a work of art, the failure of a specimen of concrete, the appearance of a newly designed piece of complex apparatus, and the presentation of various kinds of empirical evidencebased on comparative appearance, such as progressive failureof paint in weathering tests. Some writers have developed great skill in word description but few if any could compete with an aerial photograph in describing the effects of the atomic bomb dropped on Nagasaki. Photographs are especially valuable for reporting work done with the microscope. The crystal st,ructure .4ssociate Professor of Engineering Materinls.
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Figure 1 . Thi. photomicrogroph shows precisely the manner in which bituminovr matter i s distributed in o limertone.
stating a factor in the legend (e. g., 100X) is undesirable because the printer may have to change the scale of the photograph to fit it into a column or page; this change will make the stated magnification incorrect, while a scale marker in the field will change in the same proportion as the rest of the photograph. The use of an arrow to locate precisely a point, in the field is preferable to the use of a word description (e.g., the crystal in question is located on the top of a black vein in the lower left-hand corner of the field). A speaker using a slide can refer t n the arrow without turning from his audience and using a pointer or fumbling about trying to locate the spot. by word description. These added markings can be made with black ink (or with white ink on dark areas).
Figure 2 . A comparison of there two photographs illurtroter the importance d posing and of bockground..
They must strand out sharply; t,hey must have great contrast. Getting the M o r t Out of a Picture
Many photographs, particularly of specialized lahoratory equipment, show a confusing array of apparatus in the background. Figure 2 shows two photographs of the same carbon dioxide train. One contains a potpourri of irrelevant, confusing detail; the other focuses attention on the subject of the photographthe single unit of apparatus. A study of photographs used for advertising of equipment mill yield many pointers on advantageous posing. In most cases, the equipment can be backed by a panel or curtain of contrasting tone. Photographs must not be used indiscriminately. They often cannot replace charts, drawings, and other forms of illustration. A cut-away drawing showing the interior mechanism of a machine is usually far more valuable than a photograph of t,he exterior; the latter may be worthless. Photography can be usedas at001 to reproduce these other forms of illustration. A flowsheet draving may give information which would require several pages (or several minutes) of word description. The relative merits of photographs versus words, charts, and drawings can be considered carefully by preparation of alternates, if necessary. The matter of irrelevant photographs should not have to be mentioned, but a study of the journals proves that it must. Some writers apparently feel t,hat an article, in order to be respectable, must contain a photograph or two, regardless of specific application. Analytical balances, commercial colorimeters, test
tubes, and other standard, well-known objects have no place as illustrations in most technical reports. & . picture of a nickel mine in Sudbury, complete with the finest clouds ever photographed, may be a thing of beauty, but it has no place in a technical journal article on the cyanide method for titration of nickel. I t should be reserved for a seductive sales bulletin. The preceding statements do not mean that photographs should be unattractive. They simply mean that relevancy governs and that scientific value comes before pictorial value. If an article concerns efficient grouping of buildings around a nickel mine and includes a picture of a Sudbury mine, then a pleasing shot showing cloud formation is more attractive and more effective than a drab one. Any photographer, and especially the land-form geologist, has almost, limitless possibilities for making his photographs highly pleasing and thus better capable of attracting and holding interest. Balance of masses; off-center shots; division of the field into thirds; use of diagonals; inclusion of fore-, middle-, and background; and many other devices offer possibilities for making p h o b graphs, technical as well as nont,echnical, more interesting. Particularly in an oral report,, it is possible to build the sequence of illustrations to a climas, ending with a slide which will make a lasting impression and thus clinch the ideas presented in t,hepaper. Photographs have the disadvantage of deterioration--sometimes in great degree-in quality during the process of reproduction for publication. Only espensive methods of reproduction, not those customarily used in t,echnieal journals, can preserve fine detail and delicate tones. Because of this, only the finest of photographs should be submitted for publicatioilanything other than first-class prinds should be discarded without a qualm. I'igure 3 was made from a
Figure 3. Thir photograph, ond mony Qherr in pubiiihed moferid, might be a gome labeled "find the stole marker." A geological hommer ran b e lost on a quarry face-is o given l e d g e ten inches or ten f e e t thick? Thir picture alro illustrater who1 hoppens to a photograph o f medium (thus insufficient1 contrast, when it is reproduced for publication.
photograph of only medium contrast; the resulting cut does not have sufficient clarity of detail or contrast. Frequently field, and sometimes laboratory, photographs have no indication of scale, as illustrated by Volume 37, Number 12, December 1960
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Figure 3. The observer will not know whether a crack shown in the face of a dam is two inches or one-eighth inch wide. A ruler, a man, a pen, or some other familiar, easily recognizable object of approximately known size (sometimes exactly known size) should be included in the picture. The planted object must be readily visible-a pencil on a forty-foot quarry wall might possibly be overlooked. With few exceptions, photographs sent to the publisher should have a glossy finish. If a photograph of doubtful quality must be used, it is good practice to send both glazed and mat-type prints. The print should be at least as large as the cut for publication; if retouching is necessary it should be larger, so any extraneous marks from the retouching will be minimized. Size and shape of the illustration should be considered in relation to the size and shape of the column or page-grotesque cuts may result from required fitting unless the illustration is properly
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chosen. Photographs should be identified for processing through publication by soft pencil or ink on the backs of the prints. Pressure from a hard pencil may make a ridge on the face of the photograph, and such a ridge will make a shadow upon rephotographing for the cut. Oral reports can be made more interesting and more effective by the use of photographic slides. The audience can absorb an idea for a few seconds if it is illustrated on a screen, but word descriptions must be grasped immediately as they are spoken. The speaker must make his slides simple; a complicated table or graph will detract from his oral discussion because the audience will be trying to decipher it. The serious writer will do well to examine photographic illustrations critically while reading technical material from other authors. Photography is a valuable tool; technical writers must learn to use it.
