Joseph Niepce’s Heliographs—How Lucky Accidents aided Daguerre—Fox Talbot’s Calotypes—Photography’s Value to Science.
COUNTLESS years ago man must have noticed the action of sunlight upon his skin—how it tanned him in summer, turning him brown wherever the rays struck full upon his unprotected body. Later he discovered the bleaching action of sunlight, and used it for making white his early woven fabrics. No doubt he early recognized also the power of the sun in spring and summer upon the vegetable world—how it made grass and wheat sprout and brought out the green leaves upon the trees.
It was not, however, until modern chemistry began to supersede the alchemy of the Middle Ages that the action of sunlight upon various chemical compounds was realized. Some of these actions are very curious and interesting. For example, if equal volumes of chlorine and hydrogen gas are mixed together in the dark, they will remain without change. But the instant that the glass flask containing the mixture is exposed to the direct rays of the sun, the two gases unite with a tremendous explosion, blowing the flask to atoms. Sunlight has also a strong action upon various compounds of silver. Take a moist chloride of silver: this remains white as long as it is kept in the dark, but the very instant it is exposed to sunlight it takes a violet hue which rapidly becomes black.
So long ago as 1801 Sir Humphry Davy and Thomas Wedgwood used nitrate of silver for the purpose of making copies of objects the shadows of which were thrown upon white paper soaked in nitrate. But Davy did not know of any means for "fixing" the shadows, so it would not be correct to call his work photography. Yet Davy realized that such a means or agent was needed, for he wrote at the time: "Nothing but a method of preventing the unshaded portions of the delineation from being coloured by exposure to the light is wanting to make the process as useful as it is elegant."
Now, if asked who was the inventor of photography many would doubtless answer that it was the Frenchman Daguerre. It is true that Daguerre was the first man to produce anything resembling the modern photograph, but he was not the first to make a permanent sun picture. This honor belongs to two brothers named Niepce, who lived at Chalon, a town on the river Saône in Central France. Both had scientific tastes; and since Joseph, the elder of the two, owned a good farm, he and his brother had leisure to try all sorts of experiments. In 1806 they produced a model locomotive worked by heated air, which was reported upon by the French Institute.
About this time the new invention of lithography had just been introduced into France. Lithography is a method of printing from stone, and was invented by Aloys Senefelder in the year 1796. He patented his process in 1800, and it spread rapidly, all the best colored pictures being reproduced by this process. Quarries fit to yield lithographic stone were eagerly sought, and Joseph Niepce, among others, entered the search. He found some stones which at first seemed suitable, but, after trying them, he had to cast them aside as useless. Then the idea came to him that possibly a sheet of polished steel might be substituted for stone, and he began experiments.
One day, when busy with these labors in his little work-shop, it happened that a broad beam of sunlight streaming in through the open door produced a reflection of his own face in the polished plate over which he was bending, and the idea came to him that if he could only imprint such images by the mere action of sunlight he would have secured an invention far more important than that of Senefelder.
Joseph had at that time no knowledge whatever of the experiments of Davy and Wedgwood, and certainly could not have appreciated the enormous difficulties that lay in his way. Yet from that minute he devoted his life to the solution of the problem, and his whole mind was absorbed in the one question of whether to-morrow’s sun would produce any effect upon the new compounds which he was constantly inventing.
After a while came the knowledge that a certain black resinous substance, known in the arts as bitumen of Judea, on being exposed to the sun rapidly turned white. Already Joseph was aware that preparations of silver blacken in the sun’s rays, and, acting upon these two facts, he tried a most singular method of reproducing engravings. First he varnished the reverse side of a print so as to make it transparent, then he placed this on a leaf of metal coated with bitumen. The darker parts of the picture obstructed the rays of light, while those which were lighter allowed them to pass, and acted upon the bitumen. In this way Joseph Niepce obtained a perfect reproduction of the design in which the lights and shadows retained their natural position. By plunging the leaf of metal into a preparation of essence of lavender, the inventor found that he was able to "fix" his picture, and this was actually the first permanent sun picture ever made.
From this kind of copying Joseph went on to tackle the problem of fixing images obtained by the camera obscura, and at this he worked steadily for ten years. His chief agent was still bitumen spread upon a copper plate silvered over, but the bitumen required a very long time—no less than ten hours-to receive impressions. So long an exposure to direct sunlight was, of course, almost impossible, for not only did clouds interfere, but the sun’s position was constantly changing. Yet in 1824 Joseph Niepce did actually produce real photographs—. "heliographs", he called them; and considering the difficulties with which he had to contend, these were really wonderful productions.
Unknown to Joseph, there was at this time a man living in Paris who was engaged in similar researches. This was Louis Daguerre, a scene painter, and well known because of his invention of that kind of scenic exhibition known as the diorama. It was the special researches which Daguerre had been obliged to make into the effects of light and shade which had suggested to him the idea of trying to fix the beautiful pictures obtained by the camera obscura.
In 1827 there came to Daguerre’s ears news that an obscure farmer in a country village had succeeded in solving this difficult problem, and he at once posted off to interview Niepce. The latter, stiff at first, soon thawed, and the two went into a sort of partnership. Daguerre substituted for the pitch which Niepce had been using a resin obtained by distilling essence of lavender, but instead of washing the plate in the essence he exposed it to the action of a vapor derived from it. This quickened matters somewhat; yet even so, seven hours at least were required to obtain a picture.
Then came one of those lucky accidents which have so often aided the quick-witted inventor. Before his association with Daguerre, Joseph Niepce had endeavored to strengthen his plates by exposing them to the fumes of sulphur and iodine. It happened one day that a spoon left by accident on an iodized silver plate left a distinct impression of itself, and, noticing this, the inventor substituted iodine for the resinous substance hitherto used by them. Iodine, they found, gave to the silvered plates an exquisite sensibility to light, and the second great step toward the perfect sun picture was taken. By this means the time of exposure for outdoor objects was reduced from seven hours to three minutes, while interiors could be photographed in about half an hour.
In 1833 Joseph Niepce died, at the age of sixty-three. He was still poor and unknown, and had spent his whole life and nearly all he possessed in pursuit of an invention which he did not live to see fully perfected. The least that we of this age can do is to give the patient worker full credit for being the world’s first photographer.
Left alone, Daguerre carried on the work. Although he had succeeded in quickening the work of the sun, the impressions were still faint, and he still had no satisfactory method of developing his pictures. Again accident came to his aid. One evening Daguerre placed in a cupboard one of his silver iodine plates that had been exposed, and left it overnight. In the morning, on taking it out he was amazed to find that a picture had been developed on this plate. That day he exposed another plate, and, leaving it in the same cupboard, beheld next morning again a picture. How or why this had happened was beyond Daguerre’s imagination, but he set himself methodically to find out. In the cupboard were a quantity of chemicals of one kind and another, and Daguerre believed it was the vapor from one of these which was responsible for the seeming miracle. At last it became certain that it was a dish of mercury which had wrought the change, and so Daguerre discovered that he could develop an exposed plate by placing it in the dark, face down, over a dish of warmed mercury. A little later came the discovery that it was possible to fix the image satisfactorily by dipping the plate in a bath of sodium thiosulphate, which is, in fact, the ordinary "hypo" so well known to all photographers, amateur as well as professional.
Daguerre then made an effort to form a company to develop his new process, but was unable to do so. The long exposures still required and the high cost of making the sun pictures were against the commercial success of the new invention. His country, however, recognized the merit of Daguerre’s work, and granted him a pension of six thousand francs a year.
It is a very interesting point that Samuel Morse, the inventor of telegraphy, learned the process of photography direct from Daguerre himself, and upon his return to New York in 1840 produced the first photograph ever taken in the New World.
Meantime, in England, William Henry Fox Talbot had been busy in researches of his own, and in 1839, just six months before Daguerre published the results of his efforts, read a paper before the Royal Society on what he called "A New Art of Photogenic Drawing." This was his process: first, soaking a sheet of writing paper in brine, he dried it, then dipped it in a solution of nitrate of silver, thereby changing part of the nitrate to chloride. Paper so treated becomes sensitive to light, so that when a leaf, for example, is laid upon it between two plates of glass, and sunlight is allowed to act upon it, the paper goes black, except where it is covered, and thus a perfect outline of the leaf is obtained. It was Talbot who invented the terms "positive" and "negative" still used in photography. Two years later he invented an improved process, which he called the "Calotype." The paper negative was rendered translucent by means of wax; when placed in front of a piece of sensitized paper, prepared in the same way as that used for producing the negative, a positive print was obtained. Thus Fox Talbot must be honored as the discoverer of the means of producing any number of prints from an original negative.
By 1847 glass plates had come into general use. Niepce de St. Victor, a nephew of Joseph Niepce, had discovered a method of coating a glass plate with egg albumen, to which iodide and bromide of potassium and common salt had been added. Before exposure this plate was immersed in a nitrate of silver bath, which rendered it sensitive to light, and after exposure was developed with gallic acid and then fixed.
A few years later, in 1851, Frederick Scott Archer introduced collodion, which is a solution of cotton in nitric and sulphuric acid afterward dissolved in ether. This gave a transparent substance which could be used to coat glass plates, and the process, known as the "wet plate", lasted until it was superseded by the gelatine dry plate. Ever since those early days, not a year has passed without fresh inventions and developments in photography. Perhaps the most important have been the invention of optical glass and of new forms of photographic lenses. I shall have more to say of these subjects in a later chapter.
George Eastman, an American, brought photography within the reach of everybody when he produced his famous film camera, the "kodak."
In concluding his address to the Royal Photographic Society in 1921, the President, Dr. G. H. Rodman, said:
The introduction, in 1885, of films to replace glass and save weight, and the production, in 1903, of noncurling celluloid film, so wound on rollers as not even to require the use of a dark room for loading the camera, has had a very decided effect in the popularizing of photography, and it is chiefly due to this production of the Eastman Company that photography has been taken up by the masses. Finally, the obtaining of photographs in natural colour, rendered possible by the Autochrome process of Lumière in 1907, and in the Thames, the Paget, and the Dufay screen processes, enables the worker to secure representations on glass of objects in natural colour. The names of Lippman, Ives, and Sanger Shepherd are those of men who will long be remembered for the part they have played in the rendering of colour by photography.
What further developments there will be I do not venture to predict; but I feel sure, with the vast body of men now engaged on photographic work, that we shall have advances equal to, if not excelling, those that I have been privileged to bring before your notice this evening. . . . When we consider what was required in the days of the wet collodion plate, so much in use between 1851 and 1870, how that plate had to be sensitized on the spot, and developed as soon as removed from the camera, and for these reasons when work was done at a distance from the photographer’s dark room it was necessary to carry sensitizing baths and developing and fixing solutions, and to go out with a dark tent in which the plate could be manipulated, we must recognize the great change that has taken place in photographic procedure. Compare, for example, the ease of the use of the modern-day vest-pocket camera, with its roll film so easily inserted and removed after use, and capable of being exposed at, say, the South Pole, and then sent thousands of miles prior to development, with the difficulties which the landscape photographer of sixty years ago had to surmount, when he had to include in his armentarium a hand-cart on wheels for the transport of his developing tent and solutions, and travel with an assistant who played the part of a beast of burden! I cannot imagine a more graphic illustration of these points than that afforded by the comparison of the modern vest-pocket Kodak camera, provided with its highly corrected focusing Cooke lens of English manufacture, fitted with a reliable time and instantaneous shutter, with its autographic recording device, and not even requiring the use of a dark room for the insertion and subsequent development of its roll film. With such an instrument, capable of producing very excellent results, and weighing, as it does, about twelve ounces, it is not surprising that the practice of photography has become so popular.
Photography, at first looked upon merely as a means for making rapid and truthful portraits, has become much more than a popular hobby. Quite apart from its enormous value in the illustration of newspapers and books, it is of supreme importance to scientists, including astronomers. By using the camera in conjunction with the telescope, the most remarkable photographs have been obtained of celestial objects, and thus the details of a vast field of the heavens have been revealed as only the camera can show them.
The human eye tires and is easily deceived, but the eye of the camera is infallible, and it registers images which no human eye can behold. It has already proved to us that the number of stars is at least double that previously suspected. The face of the moon, the blazing atmosphere of the sun, the moons of our planets—all these have been faithfully recorded by the camera, and the work of its watchful eye never ceases.