1839, 31 de Janeiro - ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON - PROCEEDINGS OF THE ROYAL SOCIETY

1839 31 de Janeiro

ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON Vol. IV 1837 to 1843 London MDECCXLIII Pag. 120, 121   PROCEEDINGS OF THE ROYAL SOCIETY Nº. 36

A paper was read, entitled, « Some account of the Art of Photogenic Drawing, or the Process by wich Natural Objects may be made to delineate themselves without the aid of the Artist’s Pencil ». By H. F. Talbot, Esq., F.R.S.   In this communication the author states, that during the last four or five years he has invented and brought to a considerable degree of perfection, a process for copying the forms of natural objects by means of solar light, wich is received upon paper previously prepared in a particular manner. He observes, that a prior attempt of this kind is recorded in the Journal of the Royal Institution for 1802; by which it appears that the idea was originally suggested by Mr. Wedgwood, and afterwards experimented on by Sir Humphry Davy. These philosophers found, that their principle, though theoretically true, yet failed in practice, on account of certain difficulties; the two principal of which were: first, that the paper could not be rendered sufficiently sensible to receive any impression whatever from the feeble light of a camera obscura; and secondly, that the pictures which were formed by the solar rays could not be preserved, owing to their still continuing to be acted upon by the light. The author states that his experiments were begun without his being aware of this prior attempt; and that in the course of them he discovered methods of overcoming the two difficulties above related. With respect to the latter; he says, that he has found it possible by a subsequent process, so to fix the images or shadows formed by the solar rays, that they become insensible to light, and consequently admit of being preserved during any lengt of time: as an example of which, he mentions, that he has exposed some of his pictures to the sunshine for the space of an hour, without injury. With respect to the other point, he states that he has succeeded in discovering a method of preparing the paper which renders it much more sensitive to light than any which had been used previously; and by means of which he finds, that there is no difficulty in fixing the pictures given by the camera obscura and by the solar microscope. He states that in the summer of 1835 he made a great number of portraits of a house in the country of ancient architecture, several of which were this evening exhibited to the Society. After some speculations on the possibility of discovering a yet more sensitive paper, the author mentions, that the kind employed by him may be rendered so much so, as to become vivibly affected by the full light of the sun, in the space of half a second. The rest of this paper contains an account of various other ways in which this method may be employed in practice, according to the kind of object which it is required to copy: also, a brief mention of the great variety of effects resulting from comparatievely small differences in the mode of preparation of the paper: and, of certain anomalies which occur in the process, the cause of which has no hitherto been rendered distinctly manifest. In conclusion, the author designates this as “a new process, which he offers to the lovers of science and natura.”

1839, 21 de Fevereiro - ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON - PROCEEDINGS OF THE ROYAL SOCIETY

1839 21 de Fevereiro

ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON Vol. IV 1837 to 1843 London MDECCXLIII Pag. 124, 125, 126 * PROCEEDINGS OF THE ROYAL SOCIETY Nº. 37

A paper was read. Entitled, “ An Account of the Processes employed in Photogenic Drawing,” in a letter to S. Hunter Christie, Esq . Sec. R. S. By H. Fox Talbot, Esq., F.R.S. The subject, Mr. Talbot observes, naturally divides itself into two heads, - the preparation of the paper, and the means of fixing the design. In order to make what may be called ordinary Photogenic paper, the author selects, in the first place, paper of a good firm quality and smooth surface; and thinks that none answers better than superfine writing paver. He dips it into a weak solution of common salt, and wipes it dry, by which the salt is uniformly distributed throughout its substance. He then spreads a solution of nitrate of silver on one surface only, and dries it at the fire. The solution should not be saturated, but six or eight times diluted with water. When dry, the paper is fit for use. He has found by experiment that there is a certain proportion between the quantity of salt and that of the solution of silver which answers best, and gives the maximum efect. If the strength of the salt is augmented beyond this point, the effect diminishes and in certain cases becomes exceedingly small. This paper, if properly made, is very useful for all ordinary photogenic purposes. For example, nothing can be more  perfect than the images it gives of leaves and flowers, especially with a summer sun. The light passing through the leaves delineates every ramification of their nerves: If a sheet of paper thus prepared, be taken and washed with a saturated solution of salt, and then dried,it will be found (especially if the paper has been kept some weeks before the trial is made) that its sensibility is greatly diminished, and in some cases seems quite extinct. But if it be again washed with a liberal quantity of the solation of silver, it becomes again sensible to light, and even more so than it was at first. In this way by alternately washing the paper with, salt and silver, and drying it between times, Mr. Talbot has succeeded in increasing its sensibility to the degree that is requisite for receiving the images of the camera obscura. In conducting this operation it will be found that the results are sometirnes more and sometimes less satisfactory in consequence of small and accidental variations in the proportion employed. It happens sometimes that the chloride of silver is disposed to darken of itself without any esposure to the light: this shows that the attempt to give it sensibility has been carried too far. The object is, to approach to this condition as near as possible, without reaching it, so that the substance may be in a state ready to yield to the slightest extrancous force, such as the feeble impact of the violet rays when much attenuated. Having therefore prepared a number of sheets of paper slightly different from one another in the composh cut from cach, and having been duly marked or numbered, let them be placed side by side in a very weak diffused light for about a quarter of an hour. Then, if any one of them, as frequently happens, exhibits a marked advantage over its competitors, Mr. Talbot selects the paper which bears the corresponding number, to be placed in the camera obscura. With regard to the second object, that of fixing the images, Mr. Talbot that after having tried ammonia and several other reagents, with very imperfect success, the first which gave him a succesful result was the iodide of potassium much diluted with water. If a photogenic picture is washed over with this liquid, an iodide of silver is formed, which is absolutely unalterable by sunshine. This process requires precaution; for, if the solution is too strong, it attacks the dark parts of the picture. It is requisite therefore to find by trail proper proportions. The fixation of the pictures in this way, with proper management, is very beautiful and lasting. The specimen of lace which Mr. Talbot exhibited to the Society, and which was made fire years ago, was preserved in this manner. But his usual method of fixing is different from this, and somewhat simpler, or at least, requiring less nicety. It consists in immersing the picture in a strong solution of common salt, and then wiping off the superfltious moisture and drying it. It is sufficiently singular that the same substance which is so useful in giving sensibility to the paper, should also be capable, under other circumstances, of destroying it, but such is nevertheless the fact. Now, if the picture which has been thus washed and dried, is placed in the sun, the white parts colour themselves of a pale lilac tint; after which they become insensible. Numerous experiments have shown the author, that the depth of this lilac tint varies according to the quantity of salt used relatively to the quantity of silver. But by properly adjusting these, the images may, if desired, be retained of an absolute whiteness. He mentions also, that those preserved by iodine are always of a very pale primrose yellow, which has the extraordinary and very remarkable property of turning to a full gaudy yellow whenever it is exposed to the heat of a fire, and recovering its, former colour again when it is cold.

1839, 14 de Março - ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON - PROCEEDINGS OF THE ROYAL SOCIETY

1839 14 de Março

ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON Vol. IV from 1837  to 1843 inclusive London MDECCXLIII Pag. 131, 132, 133 * PROCEEDINGS OF THE ROYAL SOCIETY Nº. 37

A paper was also read, entitled, “ Note on the Art of Photography, or the application of the Chemical Rays of Light to the purposes of  Pictorial Representation.” By Sir John F. W. Herschel, Bart., K.H., V.P.R.S., &c. The author states that his attention was first called to the subject of M. Daguerre’s concealed photographic processes, by a note from Captain Beaufort, dated the 22nd of January last, at which time he was ignorant that it had been considered by Mr. Talbot, or by any one in this country. As an enigma to be solved, a variety of processes at once presented themselves, of which the most promising are the following; 1st, the so-called de-oxidizing power of the chemical rays in their action on recently precipitated chloride of silver; 2ndly, the instant and copious precipitation of a mixture of a solution of muriate of platina and lime-water by solar light, forming an insoluble compound, which might afterwards be blackened by a variety of agents; 3rdly, the reduction of gold in contact with deoxidizing agents; and, 4thly, the decomposition of an argentine compound soluble in water, exposed to light in an atmosphere of peroxide of chlorine, either pure or dilated. Confining his attention, in the present notice, to the employment of chloride of silver, the author inquires into the methods by which the blackened traces can be preserved, which may be effected, he observes, by the application of any liquid capable of dissolving and washing off the unchanged chloride, but of leaving the reduced, or oxide of silver, untouched. These conditions are best fulfilled by the liquid hyposulphites. Pure water will fix the photograph, by washing out the nitrate of silver, but the tint of the picture resulting is brick-red; but the black colour may be restored by washing it it over with a weak solution of hyposulphite of ammonia. The author found that paper impregnated with the chloride of silver was only slightly susceptible to the influence of light: but an accidental observation led him to the discovery of other salts of silver, in which the acid being more volatile, adheres to the base by a weak affinity, and wich impart much greater sensibility to the paper on which they are applied: such as the carbonate, the nitrate, and the acetate. The nitrate requires to be perfectly neutral; for theleast excess of acid lowers in a remarkable degree its susceptibility. In the application of photographic processes to the copying of engravings or drawings, many precautions, and minute attention to a number of apparently trivial, but really important circumstances, are required to ensure success. In the first transfers, both light and shadow, as well as right and left, are the reverse of the original: and to operate a second transfer, or by a double inversion to reproduce the original effect, is a matter of infinitely greater difficulty; and in which the author has only recently ascertained the cause of former failures, and the remedy to be applied. It was during the prosecution of these experiments that the author was led to notice some remarkable facts relating to the action of the chemical rays. He ascertained that, contrary to the prevailing opinion, the chemical action of light is by no means proportional to the quantity of violet rays transmitted, or even to the general tendency of the tint to the violet end of the spectrum: and his experiments lead to the conclusion that, in the same manner as media. Have been ascertained to have relations sui generis to the calorific rays, not regulated by their relations to the rays of illumination and of colour, they have also specific relations to the chemical spectrum, ditferent from those they bear to the other kinds of spectra. For the successful prosecution of this curious investigation, the first step must consist in the minute examination of the chemical actions of all the parts of a pure spectrum, not formed by material prisms, and he points out, for that purpose, one formed in Fraunhofer’s method, by the interference of the rays of liglit themselves in passing through gratings, and fixed by the heliostat. He notices a curious phenomenon respecting the action of light on nitrated paper; namely, its great increase of intensity, under a certain kind of glass strongly pressed in contact with it; an effect which cannot be explained either by the reflection of light, or the presence of moisture; but which may possibly be dependent on the evolution of heat. Twenty-three specimens of photographs, made by Sir John Herschel, accompany this paper: one, a sketch of his telescope at Slough, fixed from its image in a lens: and the rest copies of engravings and drawings, some revers, or first transfers; and others second transfers or re-reversed pictures.

1839, Abril - ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON - Proceedings of the royal society

1839 21 de Março

ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON Vol. IV 1837 to 1843 London MDECCXLIII Pag. 134 * Proceedings of the royal society nº. 37

IV. “Note respecting a new kind of Sensitive Paper”. By Henry Fox Talbot, Esq., F.R.S. The method of preparing the paper here referred to consists in washing it over with nitrate of siver, then with bromide of potassium, and afterwards again with nitrate of silver; drying it at the fire after each operation. This paper is very sensitive to the light of the clouds, and even to the feeblest daylight. The author supplies an omission in his former memoir on photogenic drawing, by mentioning a méthode he had invented and practised nearly five years ago, of imitating etchings on copper plate, by smearing over a sheet of glass with a solution of resin in turpentine, and blackening it by the smoke of a candle. On this blackened surface a design is made with the point of a needle, the lines of which will of course be transparent, and will be represented by dark lines on the prepared paper to which it is applied, when exposed to sunshine. The same principle may be applied to make numerous copies of any writing.

ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON

1841 10 de Junho

ABSTRACTS OF THE PAPERS, PRINTED IN THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON Vol. IV from 1837  to  1843 inclusive London MDECCXLIII Pag. 312, 313, 314, 315, 316 * Proceedings of the royal society nº. 48

5. « An account of some recent improvements in Photography. » By H. F. Talbot, Esq. F. R. S. The author had originally intended, in giving an account of his recent experiments in photography, to have entered into numerous details with respect to the phenomena observed; but finding that to follow out this plan would occupy a considerable time, he has tought that it would be best to put the Society, in the first place, in possession of the principal facts, and by so doing perhaps invite new observers into the field during the present favourable season for making experiments. He has, therefore, confined himself at present to a description of the improved photographic method, to wich he has given the name of Calotype, and reserves for another occasion all remarks on the theory of the process. The following is the method of obtaining the Calotype pictures. Preparation of the paper. – Take a sheet of the best writing paper, having a smooth surface, and a close and even texture. The watermark, if any, should be cut off, lest it should injure the appearance of the picture. Dissolve 100 grains of crystallized nitrate of silver in six ounces of distilled water. Wash the paper with this solution, with a soft brush, on one side, and put a mark on that side whereby to know it again. Dry the paper cautiously at a distant fire, or else let it dry spontaneously in a dark room. When dry, or nearly so, dip it into a solution of iodide of potassium containing 500 grains of that salt dissolved in one pint of water, and let it stay two or three minutes in this solution. Then dip it into a vessel of water, dry it lightly with blotting-paper, and finish drying it at a fire, wich will not injure it even if held pretty near: or else it may be left to dry spontaneously. All this is best done in the evening by candlelight. The paper so far prepared the author calls iodized paper, because it has a uniform pale yellow coating of iodide of silver. It is scarcely sensitive to light, but, nevertheless, it ought to be kept in a portfolio or a drawer, until wantcd for use. It may be kept for any length of time without spoiling or undergoing any change, if protected from the light. This is the first part of the preparation of Calotype paper, and may be performed at any time. The rernaining part is best deferred until shortly before the paper is wanted for use. When that time is arrived, take a sheet of the iodized paper and wash it with a liquid prepared in the following manner: - Dissolve 100 grains of crystallized nitrate of silver in two ounces  of distilled water; add to this solution one-sixth of its volume of strong acetic acid. Let this mixture be called A. Make a saturated solution of crystallized gallic acid in cold distilled water. The quantity dissolved is very smal. Ca1 this solution B. When a sheet of paper is wanted for use, mix together the liquids A and B in equal volumes, but only mix a small quantity of them at a time, because the mixture does not keep long without spoiling. I shall call this mixture the Gallo-nitrate of silver. Then take a sheet of iodized paper and wash it over with this gallonitrate of silver, with a soft brush, taking care to wash it on the side which has been previously marked. This operation should be performed by candlelight. Let the paper rest half a minute, and then dip it into water. Then dry it lightly with blotting-paper, and finally dry it cautiously at a fire, holding it at a considerable distance therefrom. When dry, the paper is fit for use. The author has named the paper thus prepared Calotype paper, on account of its great utility in obtaining the pictures of objects with the camera obscura. If this paper be kept in a press it will often retain its qualities in perfection for three months or more, being ready for use at any moment; but this is not uniformly the case, and the author therefore recommends that it should be used in a few hours after it has been prepared. If it is used immediately, the last drying may be dispensed with, and the paper may be used moist. Instead of employing a solution of crystallized gallic acid for the liquid B, the tincture of galls diluted with water may be used, but he does not think the results are altogether so satisfactory. Use of the Paper. - The Calotype paper is sensitive to light in an extraordinary degree, which transcends a hundred times or more that of any kind of photographic paper hitherto described. This may be made manifest by the following experiment: - Take a piece of this paper, and having covered half of it, expose the other half to daylight for the space of one second in dark cloudy weather in winter. This brief moment suffices to produce a strong impression upon the paper. But the impression is latent and invisible, and its existence would not be suspected by any one who was not forewarned of it by previous experiments. The method of causing the impression to become visible is extremely simple. It consists in washing the paper once more with the gallo-nitrate of silver, prepared in the way before described, and then warming it gently before the fire. In a few seconds the part of the paper upon which the light has acted begins to darken, and finally grows entirely black, while the other part of the paper retains its whiteness. Even a weaker impression than this may be brought out by repeating the wash of gallo-nitrate of silver, and again warming the paper. On the other hand, a stronger impression does not require the warming of the paper, for a wash of the gallo-nitrate suffices to make it visible, without heat, in the course of a minute or two. A very remarkable proof of the sensitiveness of the Calotype paper is afforded by the fact stated by the author, that it will take an impression from simple moonlight, not concentrated by a lens. If a leaf is laid upon a sheet of the paper, an image of it may be obained in this wav in from a quarter to half an hour. This paper being possessed of so high a degree of sensitiveness is therefore well suited to receive images in the camera obscura. If the aperture of the object-lens is one inch, and the focal length fifteen inches, the author finds that one minute is amply sufficient in summer to impress a strong image upon the paper of any building upon which the sun is shining. When the aperture amounts to one-third of the focal length, and the object is very white, as a plaster bust, &c., it appears to him that one second is sufficient to obtain a pretty good image of it. The images thus received upon the Calotype paper are for the most part invisible impressions. They may be made visible by the process already related, namely, by washing them with the gallonitrate of silver, and then warming the paper. When the paper is quite blank, as is generally the case, it is a highly curious and beautiful phenomenon to see the spontaneous commencement of the picture, first tracing out the stronger outlines, and then gradually filling up all numerous and complicated details. The artist should watch the picture as it developes itself, and when in his judgment it has attained the greatest degree of strength and clearness, he should stop further progress by washing it with the fixing liquid. The fixing process.-To fix the picture, it should be first washed with water, then lightly dried with blotting paper, and then washed with a solution of bromide of potassium, containing 100 grains of that salt dissolved in eight or ten ounces of water. After a minute or two it should be again dipped in water and then finally dried. The picture is in this manner very strongly fixed, and with this great advantage, that it remains transparent, and that, therefore, there is no difficulty in obtaining a copy from it. The Calotype picture is a negative one, in which the lights of nature are represented by shades; but the copies are positive, having the lights conformable to nature. They also represent the objects in their natural position with respect to right and left. The copies may be made upon Calotype paper in a very short time, the invibible impressions being brought out in the way already described: - But the author prefers to make the copies upon photographic paper prepared in the wny which he originally described in a memoir read to the Royal Society in February 1839, and which is made by washing the best writing paper, first with a weak solution of common salt, and next with a solution of nitrate of  siler. Although it takes a much longer time to obtain a copy upon this paper, yet when obtained, the tints appear more harmonious and pleasing to the eye; it requires in general from 3 minutes to 30 minutes of sunshine, according to circumstances, to obtain a good copy on this sort of photographic paper. The copy should be washed and dried, and the fixing process (which may be deferred to a subsequent day) is the same as that already mentioned. The copies are made by placing the picture upon the photographic paper, with a board below and a sheet of glass above, and pressing the papers into close contact by means of screws or otherwise. After a Calotype picture has furnished several copies, it sometimes grows faint, and no more good copies can then be made from it. But these pictures possess the beautiful and extraordinary property of being susceptible of revival. In order to revive them and restore their original appearance, it is only necessary to wash them again by candlelight with gallo-nitrate of silver, and warm them: this causes all the shades of the picture to darken greatly, while the white parts remain unaffected. The shaded parts of the paper thus acquire an opacity which gives a renewed spirit and life to the copies, of which a second series may now be taken, extending often to a very considerable number. In reviving the picture it sometimes happens that various details make their appearance which had not before been seen, having been latent all the time, yet nevertheless not destroyed by their long exposure to sunshine. The author terminates these observations by stating a few experiments calculated to render the mode of action of the sensitive paper more familiar. 1. Wash a piece of the iodized paper with the gallo-nitrate; expose it to daylight for a second or two, and then withdraw it. The paper will soon begin to darken spontaneously, and will grow quite black. 2. The same as before, but let the paper be warmed. The blackening will be more rapid in consequence of the warmth. 3. Put a large drop of the gallo-nitrate on one part of the paper and moisten another part of it more sparingly, then leave it exposed to a very faint daylight; it will be found that the lesser quantity produces the greater effect in darkening the paper; and in general, it will be seen that the most rapid darkening takes place at the moment when the paper becomes nearly dry, also, if only a portion of the paper is moistened, it will be observed that the edges or boundaries of the moistened part are more acted on by light than any other part of the surface. 4. If the paper, after being moistened with the gallo-nitrate, is washed with water and dried, a slight exposure to daylight no longer suffices to produce so much discoloration; indeed it often produces none at all. But by subsequently washing it again with the gallo-nitrate and warming it, the same degree of discoloration is developed as in the other case (experiments 1 and 2). The dry paper appears, therefore, to be equal, or superior in sensitiveness to the moist; only with this difference, that it receives a virtual instead of an actual impression from the light, which it requires a subsequent process to develope. 5. " New mode of preparation of the Daguerreotype plates, by which portraits can be taken in the short space of time of from five to fifteen seconds, according to the power of light, discovered by A. Claudet in the beginning of May 1841." Communicated by the Marquis of Northampton, Pres. R.S. " My improvement," says the author, " consists in using for the preparation of the plates, a combination of chlorine with iodine, in the state of chloride of iodine. I follow the preparation recommended by Daguerre. After having put the plate in the iodine box for a short time, and before it has acquired any appearance of yellow colour, I take it out, and pass it for about two seconds over the opening of a bottle containing chloride of iodine; and immediately I put it again in the iodine box, where it acquires very soon the yellow colour, which shows that the plate is ready to be placed into the camera obscura. I have substituted to the chloride -of iodine, chloride of bromine; and have found nearly the same reault; but I prefer chloride of iodine as producing a better effect; and besides, on account of the noxious smell of bromine. " The result of my preparation is such, that I have operated in ten seconds with the same apparatus, which, without any chlorine, required four or five minutes: when using only the original preparation of Daguerre, I have obtained un image of clouds in four seconds."