God for us to design products, we are the porters of nature!
PHOTOGRAPHY has accompanied man in almost every avenue of research. It has even performed an excellent service in psychology where, as in a realm of thought and emotion, it might hardly have been suspected of application. In the photographs of expression, abnormal facial states, of definite mental defects associated with physical features, photography has played a useful part. And it advances; methods improve and more and more skillful results are exhibited. Certainly in its artistic aspect the wonderful progress recorded in the last twenty-five years unfailingly shows how the operator becomes an artist. Delicacy and beauty, rich meanings and refined values of light and shade have been secured, its technique passing into the higher realm of artistry and composition.
How invaluable to science photography is: how in geography and travel its most obvious use has replaced the grotesquely misleading pictures of former days which were hand- made and served more to gratify .the vanity of the illustrator than to inform the reader. In palaeontology, in botany, in all branches of natural history its amazing power has been revealed. Since the invention of rapid plates and lightning shutters photography has conducted the investigator into new fields and in some cases, perhaps, has substituted its own harmless ordinance for the rapine of the rifle and the shotgun. What vast utility — which in its consequences assumes almost majestic proportions — has it not compassed in astronomy.
It is a pleasant problem to discover where photography — if applicable at all — has not been helpful. In the mineral world there are temptations for the photographer and there are conquests to be made. To make a successful picture of crystals, to portray the fine needle structure of some zeolites to give character and definition to a specimen holding two or three different minerals, to reveal the enclosures of transparent crystals, to make a mineral species speak from the picture of itself are tasks more easily discerned than solved, more easily bungled than finished. The writer responds to the kind invitation of the editor to contribute something to the ANNUAL, mere from a desire to point out a field of work not yet adequately covered than from any conviction of his own that he has in this direction done any good work himself.
Some time ago he induced his assistant, Mr. Milton G. Smith, to undertake some experiments, and the results, chosen from a large number, are here shown. They are attractive, but it is quite incontestable that they could be excelled. Mr. Smith developed with ortol. He used appropriate backgrounds and manipulated the light. In this respect much of the secret doubtless lies. The possession of a room with many windows, the use of reflectors, the careful adjustment of the specimens to the light, a perfect control of the light by shades all go towards helping out, in fact are the indispensable adjuncts of successful photographs of minerals. And then the lens! There indeed is the deus ex machine of the whole business. The lens must have depth of focus and definition for at all commensurate work. This has been demonstrated over and over again, and Mr. Smith's equipment in this respect was not altogether adequate.
Some excellent photographs of minerals have been made under the direction of F. A. Canfield, the collector and mineralogist of Dover, N. J., and they were made with a superior lens. Ordinary lenses are of course greatly assisted by "stopping down" and long exposure, though in the latter respect gypsums, apophyllites, quartzes, and, generally, white and translucent or transparent minerals must not be too carelessly treated. As I have before insisted a wide range of selection is offered in mineralogy of subjects, and more so than in almost any other branch of natural history since the variations of excellence in specimens is indefinite. It would be folly to waste time over poor specimens. But on the other hand the quality of some species is never high, and many have no photographic availability at all. One would like to see an album made up of quartzes and calcites, another of the zeolites, another of fluors, and in this last case it would be interesting to have Mr. Dugmore(1) try color plates of minerals. If his success should be as startling as that achieved with shells there would be "prolonged applause." Then again the dark and opaque minerals as the pyroxenes, amphiboles, zircons, willemite, wernerite, tourmaline, all of which form strong crystalline and rather simple outlines would make a contrasted and capital group. The gem minerals as topaz, beryl, corundum, offer attractive subjects, and invite the use of color plates.
In printing negatives of minerals by far the best results are attained by the use of silver papers or glossy velox; the detail is of course indispensable and it is secured on these papers. Surface markings, the pits, erosion or etched faces, wrinklings, truncations, inclusions, all the numerous minute features of a mineral deserve attention, and, if caught, greatly enrich and improve the picture. I have seen a fair photograph of Natrolite, which is an acicular mineral forming frequently delicate tufts, like small pincushions, bristling with its emergent needles, printed on dull velox paper, and the cushiony features became simply white spots, characterless and unmeaning. The same negative printed on glossy velox showed the delicate hairs radiately pushed out from the light background, an altogether different and a very serviceable effect. And yet — one never can tell! Just after recommending above a universal application of glossy velox for mineral prints I find that the quality of some negatives demands its rejection. To acquire a just realization of what paper to use for a negative perhaps nothing does but experiment. And yet generally a negative of detail will have its beauties best exhibited in mineralogical studies on glossy velox or silver papers properly toned.
As regards the subjects presented with this short notice, Fig. 1 fairly well shows a glistening black heap of crystals of hematite, opaque and simply lustrous, upon a rock fragment of quartz crystals (out of focus). Fig. 2 shows a series of geniculated rutiles, those exquisite twinning groups which may form a closed polygon, or (as in the example on the lower left hand corner) a succession of elbow joints. A more searching lens would have improved this result. Fig. 3 is attractive and is printed on a half-tone velox. The effect of this in the velox print is immensely heightened by holding it against the light, letting the light enter it and give it relief. But the picture is quite unable to produce the exact effect of the original specimen. That is a spherical surface covered over with projecting twin crystals which intersect or unite in leaf-like sheets, of a wonderful beauty. The lens here again has failed in individualization and depth. The result is sensibly abortive. The specimen would offer a good crucial test to a fine instrument. Fig. 4 offers much less difficulty, and naturally elicits attention from the beautiful reticulation it exhibits. It is a carbonate of lead of unusual perfection. Fig. 5 shows a group of pink translucent beryls impacted in a mass of lithia, mica, and tourmaline. The faces and edges are here detailed with some skill.
The above examples scarcely do more than call attention to a very wide field of photographic experimentation, which while occupied, in a measure, might tempt fastidious operators to enter it as, to them, an untried and novel area of effort.
Scientific requirements compel the photographer to introduce some sort of a scale by which the original size of the specimen, unless of natural size in the photograph, can be deduced. It is customary to use an inch rule or just one inch mark, but a very ingenious and adequate plan was devised and utilized by Mr. F. A. Canfield in his excellent work. He secured a steel ball of exactly one inch in diameter, and placing this at the base of the specimen photographed, secured an almost absolutely trustworthy result, the steel ball being easily manipulated and not readily displaced or shifted.
There is another consideration which occurs to me, though it would naturally suggest itself to any practical photographer, especially those engaged in the reproduction of "still life," and that is the control of the highlights. Minerals have glossy, very lustrous, surfaces and if too much light is admitted halation over these surfaces takes place, and the prints are spotted, unreal, and worthless. It is quite usually found therefore that the diffused light of even dull days works advantageously. The chaotic reflections from such faces in minerals obscure and break the edges of the crystals while they greatly interfere with the penetration of the lens into the cavities. There are, on the other hand, dull surfaces of minerals, absorbent colors, and the use of artificially directed light, as with small hand mirrors and where interior districts are to be illuminated, can be usefully invoked.
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