As time went on and observations of men became more definite, we obtain records of facts that were noted with regard to the action of light upon certain chemical compounds. You know those old alchemists had queer ideas, one in regard to their elixir of life, and another that they could turn the baser metals into gold. They discovered a material in the silver mines of the Hartz Mountains which they called “luna cornea.” The word luna was at that time applied to silver. Luna cornea was horn silver—what we know to-day as silver chloride. They noted that when this was first brought from the mine it was white and that after it had been exposed to the air and the sunlight it turned black, and they also noticed that it was only the surface that turned black—that if they scraped the surface off it was white underneath. They also found that if they kept it in the mine it did not get black. This observation was made about 1550 by Frobrishes, one of the early workers in chemistry; but you must remember that they were not studying the action of light upon this substance. Their sole object was the turning of the baser metals into gold, and therefore they did not pay much attention to this idea, although this fact was placed on record.
Some time after this we learn that a German named Schultze made copies of drawings with a mixture of chalk and silver nitrate spread on a level surface. The time of this is doubtful, but it was probably about the year 1700. He passed the light, as he says, through translucent paper (made translucent with oil or wax), and objects placed upon the paper left a white impression on the mixture of chalk and silver nitrate—or, as he called it, “lunar caustic.” This was in about 1700, as I said. About fifty years after this time (and indeed it was a little more, it was seventy years, in 1777) Scheele, the Swedish apothecary’s assistant, took up the examination of this horn silver. It seemed to him well worthy of study; and as the result of his work he obtained the first germs that led to the art of photography. But before Scheele could have prosecuted his researches, and before photography could make any important advances, there were two other discoveries in science—and in optics particularly—that had to be made. The first of these was the decomposition of white light, by Sir Isaac Newton, by which he obtained the prismatic colors; that is to say, the colors that we know as violet, indigo, blue, green, and so on down to the red. That was the first step. The next step was the discovery by Baptiste Porter, an Italian, in Naples, which preceded the discovery of Newton (it was about 1590), that a small opening in a dark chamber produced an inverted image on the wall of the chamber. So that between 1590 and 1666 Baptiste Porter and Sir Isaac Newton paved the way for the researches of Scheele upon the action of light upon this simple substance, as they called it, “luna cornea” or chloride of silver. Now Scheele, therefore, at his time, 1777, knew of the discovery of the prismatic colors, or the decomposition of white light by Sir Isaac Newton, and he made the experiment of submitting this horn silver or silver chloride to the action of light after the light had been passed through a prism and he found the light as we know it to consist of violet, indigo, blue, green, yellow, orange and red. Placing the silver chloride in this band of colors, he discovered the important fact that in the red rays the silver chloride received no change—that there was no change made in it. But, as he got along toward the other end of the spectrum, and got into the green and the blue and the indigo and the violet, he found that the color of the silver chloride changed much more rapidly, and he found that the most active in its effect upon the silver chloride were the blue and violet rays. In addition to this fact he found that the light discolored the silver chloride. Scheele still further proved that the silver chloride was decomposed by the light, and that chlorine gas, or, as he called it, dephlogisticated marine acid gas, was produced. He became acquainted with this previously from his experiments on the mineral braunstein with muriatic acid. So that when he perceived the odor of the chlorine from the decomposition of the silver chloride, he recognized the gas at once, and he says: “When this silver chloride turns black it gives out chlorine,” and that was a very important fact. At the red end of the spectrum he found there was little or no effect upon the silver chloride. This was the principle of the camera obscura, and the principle of the camera obscura is the principle of the photographic camera to-day. Practically the photographic camera consists of a dark box, with a hole at one end and at this end there is a place to receive an image. Instead of having a lens there in the front of the camera, as was formerly the practice, it is perfectly possible to get the picture with a small opening, say an eighth or sixteenth of an inch in diameter, and, furthermore, that is the most perfect picture you can get in a camera—a picture without a lens. Now, that is a strange statement, and perhaps in these days it may appear a little wild; but (exhibiting a photo about 5 × 7) there is a picture made with an opening not larger than a pinhole, and it is a good deal better than many of the pictures taken by the amateurs to-day. This opening being so small necessitates a good deal of time in the action of the light upon the sensitive silver salts behind, and that is the object of placing the lens there. By placing the lens here, instead of having a small opening, you make a larger opening which collects the light in the same manner, brings it to the focus and then the rays diverge again and you get the picture. Now, the rays as they pass through the opening without a lens, begin to diverge as soon as they are in the camera, but with a lens there they are brought together first and then cross and then you get the picture. That is the first step, then, in photography, the production of images by the camera obscura—and that is all the photographic camera consists of—a modification of it. Now, when the facts ascertained by Scheele, i.e., the action of light upon silver chloride—turning it black and producing gas (and by the way Scheele never found out what this gas was and to-day it is a matter of controversy and a problem among chemists)—with the facts ascertained by Scheele, in regard to the action of light Thomas Wedgewood and Vueder made pictures, in 1802. These pictures were very peculiar. They spread upon paper and upon glass plates that had some gummy material upon them silver chloride—as a precipitate, and then they set their subjects up, so as to get a profile shadow with a strong light upon the surface. Now, where the light passed, of course they got a black mark upon the silver chloride, but the silhouette of the face was in white. Now, that was very remarkable, because they got some very remarkable pictures of which drawings were made. They were white silhouettes on a black background, but remember that the pictures that were thus made, the white silhouettes (if I may use the term) were made by the action of some light. If you wanted to copy them you had to copy them out of the light; otherwise the whole mass would get black, and that was the difficulty. In other words, the white impression could only be examined by candle or some other weak light, and they ultimately became shrouded in darkness and were lost—so we have now none of those pictures.
While they were experimenting in England, a man named Niepse, a Frenchman, was at work upon the same subject—the action of light upon various materials, but in a somewhat different direction. In 1813, or probably before that time, he discovered that certain kinds of bitumen were soluble in oil of lavender, and that when you exposed these pieces of bitumen to some light the oil of lavender would not dissolve them any more. He conceived the idea (how, is not on record), but he thought that if he could coat plates with this bitumen and then expose them to light in a camera he could get a picture upon this bitumen, and where the light had acted the bitumen would be insoluble in oil of lavender. Where the light had not acted that he could dissolve it out. He proceeded to do this, and succeeded in getting pictures upon metal plates. He then, afterwards, etched the plates and thus got a perfect drawing or picture. So he used it simply as a means to produce a picture by etching. Now, understand, using the camera, he obtained an impression upon metal plates coated with bitumen. After exposing the plates in the camera he washed them in oil of lavender and then an etching fluid, and cut the impression into the matter and then they were printed. Some of these pictures are still in existence, they say. I have never seen any of them. After a time the plates were cleaned, and by the help of an etcher’s tools or an engraver’s tools they were cut still deeper and made very good engraving plates; so that his object was not simply to etch them but to produce plates for engraving.
While this was going on Herschel made an important discovery in 1819, and that was that chloride and bromide and iodide of silver were not soluble when blackened by light. He found that after you had exposed these materials to the light—this silver iodide, bromide or chloride—and had washed all these with hypophosphite of sodium, they would not dissolve. That was important. That made it possible to preserve the silhouette pictures devised or discovered by Wedgewood and Vueder. Therefore, after exposing the plates in the camera, as did Niepse, the Frenchman, he washed them in a solution of hypophosphite of sodium. That took off the chloride of silver that was not acted upon by the light and he preserved the pictures. Some of the first pictures that he made were rather curious. I have not one of his original pictures; I wish I had, but I have a picture made in the same manner. He took a piece of paper and saturated it with salt (he said that he used Bristol drying paper, which was a peculiar paper, made at that time in England). This was soaked in chloride of sodium or common salt, and then it was dipped and had flowed over it nitrate of silver. Therefore he had in the pores of the paper chloride of silver in very intimate contact with the paper. Then he took such objects as ferns and pieces of paper, cut it in various shapes, and laid it on the paper. That produced such an effect as where the objects had laid they had the white impression. If you took this out in the sunlight it would all get black. But he made this important discovery and thus preserved the picture. This was the first photograph made. We do that to-day, and produce other pictures with various other compounds, but I will speak of that later.
In the year 1824 we hear of another Frenchman (now, remember this was a long while ago, in 1819, and we had no photographs yet, although you might call that a photograph (exhibiting the fern picture) yet it is not). In the year 1824 we hear of another Frenchman who was a scene-painter at a theatre in Paris, and he had been using the camera obscura to obtain pictures from nature from which to paint his scenery. That is to say he had a tent built something like that (drawing figure on blackboard) with a lens something like that that was part of a right angled prism, and this light coming from the view, the image was formed in here and spread out upon a table from which he could make a drawing. He used that and was much annoyed at the time it took to get those pictures. He was very impatient, like a great many other Frenchmen. He conceived the idea of “fixing these pictures” as he called them. He did not want to have the trouble of drawing them. He said: “If I could only find some way of getting that fixed on the surface without the trouble of drawing it it would be a great convenience.” This Frenchman was Louis Daguerre, really the father of photography. Now he worked independently for some time, when he met Niepse, the Niepse that had been working on bitumen and oil of lavender, and they formed a kind of partnership in 1829. Now, remember, 1819 was the time that Sir John Herschel had discovered hypophosphite of sodium and its action on these silver compounds. They formed a partnership in order to work out “scene pictures” as they called them. In the year 1833 Niepse died—got tired of the work pretty much, I suppose—and Daguerre continued the work. What his early experiments were we have very doubtful records of. Daguerre did not seem to keep very good records. In the year 1839, little more than fifty years ago, he communicated to the French government a method for making pictures in the camera upon metallic plates. In other words he divulged the secret of the first photographic picture we have—the daguerreotype. This was such a great success and such a wonderful discovery that the French government pensioned Daguerre for his life time, and by an agreement with them the process became public property on August 10th, 1839. Now I have the good fortune to have here to-night the daguerreotype apparatus. This is practically all the paraphernalia of the daguerreotype. First of all was the camera (and you must pardon the condition of it as it is almost forty years old). I know of no other complete set in the United States, so this is rather a relic, and it requires a good deal of care in handling it for it almost falls to pieces (showing the apparatus). Here is where the lens was put and in here is where the plate holder was put. They first had to fix the lenses in the ordinary way with ground glass. Then they had a plate-holder something like ours, that they put the metallic plate in. Now having fixed it, the next thing to do was to present to the sitter this metallic plate, and I have here one of just such plates. Now, into this plate-holder are fitted “kits” as we call them to hold different sized plates. Unfortunately part of this apparatus is lost; i.e., to say all these little details of kits, but they could all be made out of little pieces of wood. Now, the daguerreotype is this: They take a silver-copper plate (a piece of copper plated with silver. When they first did this, they used to solder upon copper plates a piece of silver, then put it in a press and roll it out. After that time, in latter years when the galvanic battery had been discovered and was in common use, they electroplated it). Now, this particular plate was put into a holder that was held like that. Now the small boy was given one of the buffers or he was put at a wheel that had upon it a backing of felt and on the front of it was chamois leather (it is now long gone on this one—been rubbed off). This plate was then rubbed with a great deal of dexterity and you had to be very careful that you did not scratch it. That was the most important thing about them. It spoilt the picture if you scratched them. They had to be perfectly smooth. As I said, this was sometimes done by holding the plate on a wheel, but the ordinary way was by using one of these buffers. The silver plate was taken out by undoing this screw at the corner. Now, the first thing to do with it, then, is to make it sensitive. It is merely a silver surface now. It was made sensitive by placing it in one of these boxes (showing it) called coating boxes. Now that plate was put into that box (showing the same box), and see there is the lime in the box and it is now probably forty years old, having never been disturbed. In that lime was placed bromine, and it was then covered with a glass cover that fits over this glass trough or dish—it is rather deep. This was then placed with a little pressure—in order to keep the box tight and not let the bromine fumes get all over the studio—and they put the plate in here and pulled this over, so, leaving it there a certain number of minutes, and by action of the bromine vapor it becomes coated with bromide of silver. Then they either put some iodine into this same box or they had an iodine box. After the plate was in there a few minutes, they took it out and put it in there and gave it a dose of bromine. It was found, and by whom I am not sure, that the addition of a little iodine or a small proportion of iodide of silver with iodine of silver gave better effects. So it was then taken out and it was sensitive to light. Now, Daguerre discovered all that. This was then put in the plate holder and exposed in the camera and he got a picture. And it bothered him a great deal, for it faded. If he put that hypophosphite of sodium on it that our friend Herschel discovered, it cleaned the whole picture off. There was not enough of it. So he watched and watched and was weary with making these pictures and having them fade, until he went one day to a closet where he had a lot of these pictures stored, and he was delighted to see that the picture of a certain monument (I think it was) that he had made he thought on that plate some time before, and it was a good picture and a permanent picture. How it came about puzzled him a great deal. In looking around the closet where these pictures were exposed—where these plates were stored—he found that for some reason or other the bottle of mercury had been broken, and he tried almost every imaginable material in the closet, and at last it struck him it might be mercury. Well, he put some mercury on the plate and he ruined it. “Well, no,” he says, “it is not mercury but mercury in a very fine state. I wonder if it is the Vapor of Mercury?” He tried it and found that it was. That led to the development of the daguerreotype. Then all he did with a plate was to put it into a vessel with a few drops of mercury, and underneath a little spirit lamp. Then he would put the plate in and watch the heat (some now have a thermometer) and he would just pick it up every once in a while to see how it is developing. That process gave to him the first picture, the daguerreotype, and those are to-day the handsomest pictures ever made by photography. I have two or three of them which are partly spoiled, but to-day they far surpass anything we have ever since done in the science of photography. After the mercury process, it was very easy to wash the plate off. The object of the development was this: that where the light had acted there the mercury seemed to take hold and bring out the picture. Where the light had not acted you could dissolve the silver surface off with cyanide of potassium, which was generally used. But, if you will look at this old-fashioned daguerreotype, you will see that you had to look at them in a certain light; otherwise, you could see nothing.
Sometime afterwards a man named Fitsherbert, a Frenchman, conceived the idea of changing this peculiar picture in silver plate into a gold picture. In other words, he put into the plate a little chloride of gold and produced a daguerreotype which can be seen pretty clearly by looking squarely at it.
The beginning of the daguerreotype flourished only a short time. While Daguerre and others were working at the daguerreotype, Fox Talbot, a rich Englishman, took up the subject from another point of view. He conceived the idea of making a negative. Of course, every picture you took by Daguerre’s method you had to make a sitting for it. Such are the pictures up in the School of Mines of William Lloyd Garrison and Daniel Webster. They had to sit right down in front of the box, and copies could not be had. That was the trouble with the daguerreotype. You had one picture for every sitting. To make the difference between the positive and negative more clear, I have brought here to show you to-night (producing them) some positives and negatives printed on the same piece of paper. When the picture comes out of the camera and the plate is developing (exhibiting it) that is what it looks like—where the light struck all the light parts of the picture are black, and where the light did not strike all the black parts of the picture are white. If I take the same surface, containing the bromide of silver, iodide of silver or chloride of silver, and place it underneath that and expose it to the sunlight, where the light strikes through it will produce black, just as in the original object, and when I get through I get the positive. So there is a negative and there is a positive from the same picture. Now, that was Fox Talbot’s idea. He says “If I can do that, I can make pictures ad libitum.” With this object in view he coated paper with silver chloride. He exposed it then in the camera, fixed it in a solution of salt—common salt or iodide of potassium—and when he got through the picture was a permanent one, because the iodide of potassium dissolved out the white parts that were not affected by the light. From this negative he obtained other prints.
Now, various modifications of Fox Talbot’s process, were brought out, and a man named LaGray, I think (or at least it was just about the time he lived) conceived the idea of making these pictures more transparent by waxing them. That was the first good negative we had. It was a modification of Fox Talbot’s idea, only he waxed the paper. Then about the same time it was found that a mixture of chloride of iron and cyanide of potassium, when mixed together were acted upon by light. Herschel discovered this, and that was the way we obtained the blue print, which is far older than the photograph. Sir John Herschel found that a mixture of chloride of iron and cyanide of potassium, when exposed to sunlight made Prussian blue. So that if you take paper and coat it with this mixture and then expose it under a negative you get a blue picture.
The trouble with these paper pictures was that you could not eliminate the grain of the paper, and if you will examine these close enough you will see that they are blurred. This one printed from that particular negative is blurred—very much blurred. These sensitive silver compounds are so sensitive that the grain of the paper produces an impression. Now, in 1848, Niepse, a nephew of the first Niepse, thought it would be a good idea to use glass plates coated with albumen. He took chloride or iodide of silver, mixed it with white of egg, spread it on plates, heated the plates, which, of course, coagulated the albumen, and that fixed his film upon the glass plates. That was quite a step. Now, we had gotten rid of the paper. By the way, I made a little mistake there about the way he got the picture. He got the picture by putting salt in the albumen and then coagulating it, and then he dipped the plate into a solution of silver nitrate and in that way got the precipitate in the film itself. This was important but troublesome and not always successful.
Now, a few years before another discovery was made. Remember that this was in 1848 that Niepse worked with the albumen process. In 1840, Schurben, a Swiss chemist, discovered gum cotton. This gum cotton is a nitrated compound of cotton, made by the action of concentrated sulphuric and nitric acids upon cotton. Sometime afterwards Maynard, a Yankee, in Boston, discovered that this gum cotton was soluble in alcohol, and ether, and then he found that by evaporating the substance he got the thin film of collodion. Scott Archer, an Englishman, conceived the idea of using this film as a vehicle for these particularly sensitive silver salts for photographing. His method was pretty much that which is followed to-day and that is still in use to quite a large extent.