[Experiments of Wedgewood and Davy]—[Niépce’s Heliography]—[Daguerre and the Daguerreotype]—[Fox Talbot Makes First Proofs from Negatives]—[Sir John Herschel Introduces Glass Plates]—[The Collodion Process]—[Silver and Carbon Prints]—[Ambrotypes]—[Emulsions]—[Dry Plates]—[The Kodak Camera]—[The Platinotype]—[Photography in Colors]—[Panorama Cameras]—[Photo-Engraving and Photo-Lithography]—[Half Tone Engraving].
““Art’s proudest triumph is to imitate nature.””
When nature paints she does so with the brush of beauty, dipped in the pigment of truth. The tender affection of a ray of light touches the heart of a rose, brings a blush to its cheek, and life, becoming the bride of chemical affinity, blooms into surpassing beauty and loveliness. Photography is closely allied to nature’s painting, for just as light brings into existence nature’s living beauties, so does light fix, preserve, and perpetuate these beauties by the same subtile and mysterious agency of a quickened chemical affinity. Photography is both an art and a science, and as such is both beautiful and true. It is an art intimately associated with the tenderest affections of the human heart in keeping alive its precious memories. By it the youthful sweetheart of long ago, the loving face of the departed mother, and the cherished form of the dead child are brought back to us in familiar presence, while our great men have become the every-day friends and ideals of the common people. What an enrichment and satisfaction it would have added to our lives if the art had been coeval with history, and all the world’s exalted scenes and faces had come to us through the camera with the knowledge of absolute truth and fidelity. But not only in portraiture is photography a great art, for it catches the stately pose of the mountain, the grandeur of the sea, the beauty of the forest, or the majesty of Niagara Falls, and brings them all home to us, even to the vision of the bed-ridden invalid. The camera alike records the secrets of the starry heavens and the bacteria of the microscopic world. Hanging on the tail of a kite it photographs the face of mother earth, and, acting quicker than the lightning, it catches and defines the path of that erratic flash. It plays the part of a private detective, and its testimony in court is never doubted. The architect, engineer, and illustrator find it in constant requisition. By the aid of the Roentgen Rays, it locates a bullet in a wounded soldier, and takes a picture of one’s spinal column. In fact, it sees and records things both visible and invisible, acts with the rapidity of thought, and is never mistaken.
The art of photography, named from the two Greek words φωτος γραφη (the writing of light), is a comparatively new one, and belongs entirely to the Nineteenth Century. It was known to the ancient alchemists that “horn silver” (fused chloride of silver) would blacken on exposure to light, but there was neither any clear understanding of the nature of this action, nor any application made of it prior to the year 1800. We now know that the art of photography is dependent upon the actinic effect of certain of the rays of the spectrum upon certain chemical salts, notably those of silver and chromic acid, in connection with organic matter. The rays which have this effect are the blue and violet rays at one end of the spectrum, and even invisible rays beyond the violet, the red and yellow rays having little or no such actinic effect.
That which made photography possible for the Nineteenth Century was the philosophical observation of Scheele, in 1777, upon the decomposing influence of light on the salts of silver, and the superior activity of the violet rays of the spectrum over the others in producing this effect. In 1801 Ritter proved the existence of such invisible rays beyond the violet end of the visible spectrum by the power they possessed of blackening chloride of silver.
Earliest Application of Principles.—The first attempt to render the blackening of silver salts by light available for artistic purposes, was made by Wedgewood and Davy in 1802. A sheet of white paper was saturated with a solution of nitrate of silver, and the shadow of the figure intended to be copied was projected upon it. Where the shadow fell the paper remained white, while the surrounding exposed parts darkened under the sun’s rays. There was, however, no means of fixing such a picture, and in time the white parts would also turn black.
Introduction of Camera.—The camera obscura, a very old invention designed for the use of artists in copying from nature, was at a very early period brought into this art, but it was found that the chemicals employed by Wedgewood and Davy were not sufficiently sensitive to be affected by its subdued light. In 1814, however, Joseph Nicéphore Niépce, of Chalôns, invented a process that utilized the camera, and which was called “Heliography,” or sun drawing. In 1827 he discarded the use of silver salts, and employed a resin known as “Bitumen of Judea” (asphaltum). A plate was coated with a solution of this resin and exposed. The light acting upon the plate rendered the resin insoluble where exposed, and left it soluble under the shadows. Hence, when treated with an oleaginous solvent the shadows dissolved out, and the lights, represented by the undissolved resin, formed a picture, which was in reality a permanent negative. The process, however, was slow, requiring some hours.
The Daguerreotype.—In 1829 Niépce and Daguerre became partners, and in 1839, after the death of the elder Niépce, the process named after Daguerre was perfected (British patent No. 8,194, of 1839). He abandoned the resin as a sensitive material, and went back to the salts of silver. He employed a polished silver surfaced plate, and exposed it to the action of the vapors of iodine, so as to form a layer of iodide of silver upon the surface, which rendered it very sensitive. By a short exposure in the camera an effect was produced, not visible to the eye, but appearing when the plate was subjected to the vapor of mercury. This process reduced the time required from hours to minutes, and as it involved the production of a latent image, which was subsequently developed by a chemical agent, it represented practically the beginning of the photographic art as practiced to-day. Daguerre sought also to permanently fix his pictures, but this was accomplished only imperfectly until 1839, when Sir John Herschel made known the properties of the hyposulphites for dissolving the salts of silver. In 1844 Hunt introduced the protosulphate of iron as a developer.
Production of Positive Proofs from Negatives.—This was first done by Mr. Fox Talbot, of England, between 1834 and 1839. In his first communication to the Royal Society, in January, 1839, it was directed that the paper should be dipped first in a solution of chloride of sodium, and then in nitrate of silver, which, by reaction, produced, on the face of the paper, chloride of silver, which was more sensitive to the light than nitrate of silver. The object to be reproduced was laid in contact with the prepared paper, and exposed to the light until a copy was produced which was a negative, having the lights and shadows reversed. A second sheet was then prepared, and the first or negative impression was laid upon it, and used as a stencil to produce a second print which, by a reversal of the lights and shadows, formed an exact reproduction of the original. In 1841, British patent No. 8,842 was obtained by Mr. Talbot, for what he called the “Calotype,” and which was afterward known as the “Talbotype.” A sheet of paper was first coated with iodide of silver, by soaking it alternately in iodide of potassium and nitrate of silver, and was then washed with a solution of gallic acid containing nitrate of silver, by which the sensitiveness to light was increased. An exposure of some seconds or minutes, according to the brightness of the light, produced an impression upon the plate, which, when treated with a fresh portion of gallic acid and nitrate of silver, developed into the image. After being fixed it formed a negative from which any number of prints might be obtained. The Talbot process represented a great advance in this art. Glass plates to retain the sensitive film were introduced by Sir John Herschel in 1839, and were a great improvement over the paper negatives, which latter, from lack of transparency and uniformity in texture, had prevented fine definition and sharpness of outline. Blue printing was also invented by Sir John Herschel in 1842, and he was the first to apply the term “negative” in photography. In 1848 M. Niépce de St. Victor, a nephew of Daguerre’s former partner, applied to the glass a film of albumen to receive the sensitive silver coating.
Collodion Process.—The most important step in the preparation of the negative was the application of collodion. This is a solution of pyroxilin in ether and alcohol, which rapidly evaporates and leaves a thin film adhering to the glass. M. Le Gray, of Paris, was the first to suggest collodion for this purpose, but Mr. Scott Archer, of London, in 1851, was the first to carry it out practically. A clean plate of glass is coated with collodion sensitized with iodides of potassium, etc., and is then immersed in a solution of nitrate of silver. Metallic silver takes the place of potassium, forming insoluble iodide of silver on the film. The plate is then exposed and the latent image developed by an aqueous solution of pyrogallic acid, or protosulphate of iron. When sufficiently developed, the plate is washed, and the image fixed by dissolving the unacted-upon iodide of silver with a solution of cyanide of potassium or hyposulphite of soda. This completed the negative or stencil from which the positives are printed by passing rays of light through it upon sensitive paper.