1833

1833

WILLIAM HENRY FOX TALBOT, inicia as suas experiências fotográficas.

1835

1835

WILLIAM HENRY FOX TALBOT, obtém imagens negativas sobre papel, a que dá o noma de calotypos.

1839, 25 de Janeiro

1839 25 de Janeiro

MICHAEL FARADAY, apresenta à Royal Institution os desenhos photogénicos de WILLIAM HENRY FOX TALBOT.

1839, 28 de Janeiro

1839 28 de Janeiro

É recebido na  Royal Society, o texto de WILLIAM HENRY FOX TALBOT (11/2/1800-17/9/1877) Some Account of the Art of Photogenic Drawing Or, the process by which Natural Objects may be made to delineate themselves, without the aid of the Artist’s Pencil

1839, 31 de Janeiro - Some Account of the Art of Photogenic Drawing Or, the process by which Natural Objects may be made to delineate themselves, without the aid of the Artist’s Pencil.

1839 31 de Janeiro

É lido, na Royal Society, o texto da autoria de Henry Fox Talbot   Some Account of the Art of Photogenic Drawing Or, the process by which Natural Objects may be made to delineate themselves, without the aid of the Artist’s Pencil.     In the spring of 1834 I began to put in practice a method which I had devised some time previously, for employing to purposes of utility the very curious property which has been long known to chemists to be possessed by the nitrate of silver: namely its discoloration when exposed to the violet rays of light. This property appeared to me to be perhaps capable of useful application in the following manner. I proposed to spread on a sheet of paper a sufficient quantity of the nitrate of silver; & then to set the paper in the sunshine, having first placed before it some object casting a well defined shadow. The light, acting on the rest of the paper would naturally blacken it, while the parts in shadow would retain their whiteness. Thus I expected that a kind of image or picture would be produced, resembling to a certain degree the object from which it was derived. I expected however also, that it would be necessary to preserve such images in a portfolio, & to view them only by candlelights: because, if by daylight, the same natural process which formed the images, would destroy them, by blackening the rest of the paper. Such was my leading idea, before it was enlarged & corrected by experience. It was not until some time after, & when I was in possession of several novel & curious results, that I thought of enquiring whether this process had been ever proposed or attempted before? I found that in fact it had: but apparently not followed up to any extent, or with much perseverance, the few notices that I have been able to meet with, one vague and unsatisfactory; merely stating that such a method exists of obtaining the outline of an object, but going into no details respecting the best & most advantageous manner of proceeding. The only definite account of the matter which I have been able to meet with, is contained in the first volume of the Journal of the Royal Institution page 170. from which it appears that the idea was originally started by Mr. Wedgwood, and a numerous series of experiments made both by him & Sir Humphry Davy, which however ended in failure. I will take the liberty of quoting a few passages from this memoir. “The copy of a painting, immediately after being taken, must be kept in an obscure place. It may indeed be examined in the shade, but in this case the exposure should be only for a few minutes. No attempts that have been made to prevent the uncoloured parts from being acted upon by light, have as yet been successful. They have been covered with a thin coating of fine varnish, but this has not destroyed their susceptibility of becoming coloured. When the solar rays are passed through a print & thrown upon prepared paper, the unshaded parts are slowly copied: but the lights transmitted by the shaded parts, are seldom so definite as to from a distinct resemblance of them, by producing different intensities of colour. The images found by means of a camera obscura have been found to be too faint to produce in any moderate time, an effect upon the nitrate of silver. To copy these images was the first object of Mr. Wedgwood, but all his numerous experiments proved unsuccessful.” These are the observations of Sir Humphry Davy. I have been informed by a scientific friend that this unfavourable result of Mr. Wedgwood’s & Sir Humphry Davy’s experiments, was the chief cause which discouraged him from following up with perseverance, the idea, which he had also entertained of fixing the beautiful images of the camera obscura. And no doubt, when so distinguished an experimenter as Sir H. Davy announced “that all experiments had proved unsuccessful” such a statement was calculated materially to discourage further inquiry. The circumstance also, announced by Davy, that the paper on which these images were depicted, was liable to become entirely dark; & that nothing hitherto tried, would prevent it; would perhaps have induced one to consider the attempt as hopeless - if I had not (fortunately) before I read it, already discovered a method of overcoming this difficulty, & of fixing the image in such a manner, that it is no more liable to injury or destruction. In the course of my experiments directed to that end, I have been astonished at the variety of effects which I have found produced by a very limited number of different processes when combined in various ways; and also at the length of time which sometimes elapses before the fade effect of these manifests itself with certainty. For, I have found, that images formed in this manner, which have appeared in good preservation at the end of 12 months from the time of their formation, have nevertheless somewhat altered during the second year. This circumstance added to the fact that the first attempts which I made, became indistinct in process of time (the paper growing wholly dark) induced me to watch the process of the change during some considerable time: as I thought that perhaps all these images would ultimately be found to fade away. I found however to my satisfaction, that this was not the case: and having now kept a number of these drawings during nearly five years, without their suffering any deterioration I think myself authorised to draw conclusions from my experiments with more certainty.   §.2.   Effect & appearance of these images   The images obtained in this manner are themselves white, but the ground upon which they display themselves is variously & pleasingly coloured.  Such is the variety of which the process is capable, that by merely varying the proportions & some trifling details of manipulation, any of the following colours are readily obtainable   Sky-blue Yellow Rose-colour Brown, of various shades Black Green alone, is absent from the list, with the exception of a dark shade of it, approaching to black.   The blue-coloured variety has a very pleasing effect, somewhat like that produced by the Wedgewood-ware which has white figures on a blue ground. This variety also retains its colours perfectly if preserved in a portfolio, & not being subject to any spontaneous change requires no preserving process. These different shades of colour are of course so many different chemical compounds which chemists have not hitherto distinctly noticed.   §.3.   First application of this process.   The first kind of objects which I attempted to copy by this process were flowers & leaves, either fresh or selected from my herbarium. These it renders with the utmost truth & fidelity - exhibiting even the venation of the leaves, the minute hairs that clothe the plant, &c. &c. It is so natural to associate the idea of labour with great complexity and elaborate detail of execution; that one is more struck, at seeing the thousand florets of an Agrostis depicted with all its capillary branchlets (and so accurately, that none of all this multitude shall want its little bivalve calyx requiring to be examined through a lens) - than one is by the picture of the large and simple leaf of an oak or chesnut. But in truth the difficulty is in both cases the same. The one of these takes no more time to execute than the other: for, the object which would take the most skilful artist days or weeks of labour to trace or to copy, is effected by the boundless powers of natural chemistry in the space of a few seconds. To give an idea of the degree of accuracy with which some object could be initiated by this process, I need only mention one instance. Upon one occasion, having made an image of a piece of lace of an elaborate pattern, I showed it to some persons, at the distance of a few feet, with the enquiry: whether it was a good representation? When the reply was: “that they were not to be so easily deceived; for that was evidently no picture, but the piece of lace itself." At the very commencement of my experiments upon this subject, when I saw how beautiful were the images which were thus produced by the action of light, I regretted the more that they were destined to have such a brief existence, & I resolved to attempt to find out if possible some method of preventing this, or retarding it as much as possible. The following Considerations led me to conceive the possibility of discovering a preservative process. The nitrate of silver which has become black by the action of light, is no longer the same chemical substance that it was before. Consequently, if a picture, produced by solar light, is subjected afterwards to any chemical process, the white & dark parts of it will be differently acted upon: & there is no evidence, that after this action has taken place, these white & dark parts will any longer be subject to a spontaneous change. Or, if they are so, still it does not follow that that change will now tend to assimilate them to each other. In case of their remaining dissimilar the picture will remain visible, & therefore our object will be accomplished. If it should be asserted that exposure to sunshine would necessarily reduce the whole to one uniform tint, & destroy the picture, the onus probandi evidently lies on those who make the assertion. If we designate by the letter A the exposure to the solar light; and by B some indeterminate Chemical process, my argument was this: - Since it cannot be shown à priori that the final result of the series of processes A. B. A. will be the same with that denoted by B. A. it will therefore be worth while to put the matter to the test of experiments: - viz. by varying the process B until the right one be discovered: or until so many trials have been made as to preclude all reasonable hope of its existence. My first trials were unsuccessful, as indeed I expected: but after some time I discovered amethod which answers perfectly, and shortly afterwards, another. On one of these more especially I have made numerous experiments: the other I have comparatively little used, because it appears to require more nicety in the management. It is however equal, if not superior, to the first in brilliancy of effect. This chemical change, which I call the preserving process, is far more effectual than could have been anticipated. The paper which had previously been so sensitive to light, becomes completely insensitive to it, insomuch that I am able to show the Society specimens which have been exposed for an hour to the full summer sun, & from which exposure the image has suffered nothing, but retains its perfect whiteness.   §.4.   On the Art of Fixing a Shadow   The phenomenon which I have now briefly mentioned appears to me to partake of the character of the marvellous, almost as much as any fact which physical investigation has yet brought to our knowledge. The most transitory of things - a shadow - the proverbial emblem of all that is fleeting and momentary – may be fettered by the spells of our “natural magic”, & may be fixed for ever in the position which it seemed only destined for a single instant to occupy. This remarkable phenomenon, of whatever value it may turn out in its application to the arts, will at least be accepted as a new proof of the value of the inductive methods of modern science, which by noticing the occurrence of unusual circumstances (which accident perhaps first manifests in some small degree) & by following them up with experiments, & varying the conditions of these, until the true law of nature which they express, is apprehended; conducts us at length to consequences altogether unexpected, remote from usual experience, & contrary to almost universal belief. Such is the fact, that we may receive on paper the fleeting shadow; arrest it there; & in the space of a single minute fix it there so firmly as to be no more capable of change, even if thrown back into the sunbeam from which it derived its origin.   §.5   Before going further I may however add, that it is not always necessary to use a preserving process. This I did not discover until after I had acquired considerable practice in this art; having supposed at first that all these pictures would ultimately become indistinct if not preserved in some way from the change. But experience has shown to me that there are at least two or three different ways in which the process may be conducted so that the images shall possess a character of durability, provided they are kept from the action of direct sunshine. These ways have presented themselves to notice rather accidentally than otherwise: in some instances without any particular memoranda having been made at the time; so that I am not yet prepared to state accurately, on which particular thing this sort of semi-durability depends, or what cause is best to be followed in order to obtain it. But as I have found that certain of the images which have been subjected to no preserving process, remain quite white and perfect after the lapse of a year or two, & indeed show no symptom whatever of changing: which others differently prepared (& left unpreserved) have grown quite dark in one tenth of that time – I think this singularity requires to be pointed out. Whether it will be of much value I do not know: perhaps it will be thought better to incur at first the small additional trouble of employing the preserving process, especially as the drawings thus prepared will stand the sunshine; while the unpreserved ones, however well they last in a portfolio or in common daylight, should not be risked in a very strong light, as they would be liable to change thereby even years after their original formation. This very quality however admits of useful application. For, this semidurable paper, which retains its whiteness for years in the shade, & yet suffers a change whenever exposed to the solar light, is evidently well suited to the use of a naturalist travelling in a distant country, who may wish to keep some memorial of the plants he finds, without having the trouble of drying them & carrying them about with him. He would only have to take a sheet of this paper, throw the image upon it & replace it in his portfolio.   The defect of this particular paper is, that in general the ground is not even; but this is of no consequence where utility alone & not beauty of effect, is consulted.   Portraits   Another purpose for which I think my method will be found very convenient is the making of outline portraits, or silhouettes. These are now often traced by the hand, from shadows projected by a candle. But the hand is liable to err from the true outline, & a very small deviation causes a notable diminution in the resemblance. I believe this manual process cannot be compared with the truth and fidelity with which the portrait is given by means of solar light.   Paintings on glass     The shadow pictures which are found by exposing paintings on glass to solar light, are very pleasing. The glass itself, around the painting, should be blackened: such, for instance as are often employed for the magic lantern. The paintings on the glass should have no bright yellows or reds, for these stop the violet rays of light which are the only effective ones. The pictures thus formed resemble the productions of the artist’s pencil more, perhaps, than any of the others. Persons to whom I have shown them have generally mistaken them for such, at the same time observing, that the style was new to them, & must be one rather difficult to acquire. It is in these pictures only, that as yet, I have observed indications of Colour. I have not had time to pursue this branch of the enquiry further. It would be a great thing if by any means we could accomplish the delineation of objects in their natural colours. I am not very sanguine respecting the possibility of this: yet, as I have just now remarked, it appears possible to obtain at least some indication of variety of tint.   Application to the Microscope   I now come to a branch of the subject which appears to be very important and likely to prove extensively useful - the application of my method of delineating objects, to the solar microscope. The objects which the microscope unfolds to our view, curious & wonderful as they are, are often singularly complicated. The eye indeed may comprehend the whole which is presented to it, in the field of view: but the powers of the pencil fail to express these minutiae of nature in their innumerable details. What artist could have skill or patience enough to copy them? Or, granting that he could do so, must it not be at the expense of much most valuable time, which might be more usefully employed? Contemplating the beautiful picture which the solar microscope produces, the thought struck me whether it might not be possible to cause that image to impress itself upon the paper, & thus to let Nature substitute her own imitable pencil, for the imperfect tedious & almost hopeless attempt of copying a subject so intricate? My first attempt had no success. Although I chose a light day, & formed a good image of my object, upon prepared paper; on returning at the expiration of an hour I found that no effect had taken place – I was thereupon half inclined to abandon this experiment, when it occurred to me, that there was no reason to suppose that the common nitrate of silver was the most sensitive substance that exists, to the action of the Chemical Rays: and though such should eventually prove to be the fact, at any rate it was not to be assumed without proof. I therefore began a course of experiments in order to ascertain the influence of various modes of preparation, & I found these to be signally different in their results. I considered this matter chiefly in a practical point of view; for as to the theory, I confess that I cannot as yet understand the reason why the paper prepared in one way should be so much more sensitive, than in another. The result of these experiments was the discovery of a mode of preparation vastly superior in sensibility to what I had originally employed: & by means of this, all those effects which I had before only anticipated as theoretically possible were found to be capable of realization. When a sheet of this, which I shall call “Sensitive Paper” is placed in a dark chamber & the magnified image of some object thrown on it by the solar microscope; after the lapse of perhaps a quarter of an hour, the picture is found to be completed. I have not as yet used high magnifying power, on account of the consequent enfeeblement of the light. Of course, with a more sensitive paper, greater magnifying power will become desirable. On examining one of these pictures, which I made about 3 years & a half ago, I find, by actual measurement of the picture and the object, that the latter is magnified 17 times in linear diameter, & in surface consequently 289 times. I have others which I believe are considerably more magnified; but I have lost the corresponding objects, so that I cannot here state the exact numbers. Not only does this process save our time & trouble, but there are many objects, especially microscopic crystallisations, which alter so greatly in the cause of 3 or 4 days (and it could hardly take any artist less to delineate them in all their details) that they could never be drawn in the usual way. I will now describe the degree of sensitiveness which this paper possesses - premising that I am far from supposing that I have reached the limit of which this quality is capable. On the contrary, considering the few experiments which I have made, (few, that is, in comparison with the number which it would be easy to imagine & propose) I think it most likely, that other methods may be found, by which substances may be prepared perhaps as much transcending in sensitiveness the one which I have employed, as that does the ordinary state of the nitrate of silver. But, to confine myself to what I have actually accomplished, in the preparation of a very sensitive paper. When a sheet of this paper is brought towards a window, not one through which the sun shines, but looking in the opposite direction, it immediately begins to discolour. For this reason, if the paper is prepared by sunlight, it must by no means be left uncovered, but as soon as finished be shut up in a drawer or cupboard & there left to dry: or else, dried at night by the warmth of a fire. Before using this paper for the delineation of any object, I generally approach it for a little time towards the light, thus intentionally giving it a slight shade of colour, for the purpose of seeing that the ground is even. If it appears so, when thus tried to a small extent, it will generally be found to prove so in the final result. But if there are some places or spots in it which do not acquire the same tint as the rest, such a sheet of paper should be rejected: for there is a risk that when employed – instead of presenting a ground uniformly dark, which is essential to the beauty of the drawing, it will have large white spots, - places altogether insensible to the effect of light. This singular circumstance I shall revert to elsewhere: it is sufficient to mention it here: The paper then, which is thus readily sensitive to the light of a common window, is of course much more so, to the direct sunshine. Indeed, such is the velocity of the effect then produced, that the picture may be said to be ended almost as soon as it is begun. To give some more definite idea of the rapidity of the process, I will state, that after various trials the nearest evaluation which I could make of the time necessary for obtaining the picture of an object so as to have pretty distinct outlines, when I employed the full sunshine, was half a second.   Architecture, Landscape, & external Nature   But perhaps the most curious application of this art is the one I am now about to relate. At least, it is that which has appeared the most surprising to those who have examined my collection of pictures formed by solar light. Everyone is acquainted with the beautiful effects which are produced by a Camera Obscura & has admired the vivid picture of external nature which it displays. It had often occurred to me, that if it were possible to retain upon the paper the lovely scene which thus illuminates it for a moment; or if we could but fix the outlines of it, the lights & shadows: divested of all colour; such a result could not fail to be most interesting. And however much I might be disposed at first to treat this notion as a scientific dream, yet when I had succeeded in fixing the images of the Solar Microscope by means of a peculiarly sensitive paper, there appeared no longer any doubt that an analogous process would succeed in copying the objects of external nature although indeed they are much less illuminated. Not having with me in the country a camera obscura of any considerable size, I constructed one out of a large box, the image being thrown upon one end of it by a good object glass fixed in the opposite end. This apparatus being armed with a sensitive paper was taken out in a summer afternoon & placed about 100 yards from a building favourably illuminated by the sun. An hour or two afterwards I opened the box, & I found depicted upon the paper a very distinct representation of the building, with the exception of those parts of it which were in the shade. A little experience in this branch of the art showed me, that with smaller camera obscuræ the effect would be produced in a smaller time. Accordingly I had several small boxes made, in which I fixed lenses of shorter focus, and with these I obtained very perfect but extremely small pictures: such as without great stretch of imagination might be supposed to be the work of some Lilliputian artist. They require indeed examination with a lens, to discover all their minutiæ. In the summer of 1835 I made in this way a great number of representations of my house in the country; which is well suited to the purpose, from its ancient & remarkable architecture. And this building I believe to be the first, that was ever yet known to have drawn its own picture. The method of proceeding was this: - Having first adjusted the paper to the proper focus, in each of these little cameræ, I then took a number of them with me out of doors, & placed them in different situations around the building. After the lapse of half an hour I gathered them all up, & brought them within doors to open them. When opened, there was found in each a miniature picture of the objects before which it had been placed. To the traveller in distant lands, who is ignorant as too many unfortunately are, of the art of drawing, this little invention may prove of real service. And even to the artist himself, however skilful he may be. For although this natural process does not produce an effect much resembling the productions of his pencil; & therefore cannot be considered as capable of replacing them: yet it is to be recollected that he may often be so situated, as to be able to devote only a single hour to the delineation of some very interesting locality. Now, since nothing prevents him from simultaneously disposing, in different positions, any number of these little cameræ, it is evident that their collective results, when examined afterwards, may furnish him with a large body of interesting memorials, & with numerous details which he had not had himself time either to note down or to delineate.   Delineations of sculpture.   Another use which I propose to make of my invention is for the copying of statues & basreliefs. I place these in strong sunshine, & put before them at a proper distance & in the requisite position a small camera obscura containing the prepared paper. In this way I have obtained images of various statues &c. I have not pursued this branch of the subject to any extent: but I expect interesting results from it & that it may be usefully employed under many circumstances.   Copying of Engravings   The invention may be employed with great facility for obtaining copies of drawings, or engravings, or facsimiles of M.S.S. For this purpose the engraving is pressed upon the prepared paper, with its engraved side in contact with the latter. The pressure must be as uniform as possible, that the contact may be perfect: for, the least interval sensibly injures the result, by producing a kind of clouding in lieu of the sharp strokes of the original. When placed in the sun, the solar light gradually traverses the paper, except in those placed where it is prevented from doing so by the opaque lines of the engraving. It therefore of course makes an exact images or print of the design. This is one of the experiments which Davy and Wedgwood state that they tried, but failed, from want of sufficient sensibility in their paper. The length of time requisite for effecting the copy depends on the thickness of the paper onwhich the engraving has been printed. At first I thought that it would not be possible to succeed with thick papers: but I found on trial that the success of the method was by no means so limited. It is enough for the purpose, if thepaper allows any of the solar light to pass. Then the paper is thick, I allow half an hour for the formation of a good copy. In this way I have copied very minute complicated & delicate engravings, crowded with figures of small size, which were rendered with great distinctness. The effect of the copy, though of course unlike the original, (substituting as it does lights for shadows and vice versa) yet is often very pleasing, & would I think suggest to artists useful ideas respecting light & shade. It may be supposed that the engraving would be soiled or injured by being thus pressed against the prepared paper. There is not much danger of this, provided both are perfectly dry. It may be well to mention however, that in case any stain should be perceived on the engraving it may be readily removed by a chemical application which does no injury whatever to the paper. In copying engravings &c. by this method, the lights & shadows are reversed: consequently the effect is wholly altered. But if the picture so obtained is first preserved so as to bear sunshine, it may be afterwards itself employed as an object to be copied: & by means of this second process the lights & shadows are brought back to their original disposition. In this way we have indeed to contend with the imperfections arising from 2 processes instead of one; but I believe this will be found merely a difficulty of manipulation. I propose to employ this for the purpose more particularly of multiplying at small expense copies of such rare or unique engravings as it would not be worth while to reengrave, from the limited demand for them. I will now add a few remarks concerning the very singular circumstance which I have before briefly mentioned, viz. that the paper sometimes, although intended to be prepared of the most sensitive quality, turns out on trial to be wholly insensible to light, & incapable of change. The most singular part of this, is the very small difference in the mode of preparation which causes so wide a discrepancy in the results. For instance, a sheet of paper is all prepared at the same time, & with the intention of giving it as much uniformity as possible. And yet, when exposed to sunshine, this paper will exhibit large white spots of very definite outline, where the preparing process has failed; the rest of the paper, where it has succeeded, turning black as rapidly as possible. Sometimes the spots are of a pale tint of cærulean blue, & are surrounded by exceedingly definite outlines of perfect whiteness contrasting very much with the blackness of the part immediately succeeding. With regard to the theory of this, I am only prepared to state as my opinion at present that it is a case of what is called “unstable equilibrium”. The process followed is such as to produce one of two definite chemical compounds; & when we happen to come near the limit which separates the two cases, it depends upon exceedingly small & often imperceptible circumstances, which of the two compounds shall be formed. That they are both definite compounds, is of course at present, merely my conjecture: - that they are signally different is evident from their dissimilar properties. I have thus endeavoured to give a brief outline of some of the peculiarities attending this new process, which I offer to the lovers of Science & Nature. That it is susceptible of great improvements I have no manner of doubt: but even in its present state I believe it will be found capable of many useful and important applications besides those which I have given a short account in the preceding pages.

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, 2 de Fevereiro - THE LITERARY GAZETTE AND JOURNAL OF BELLES LETTRES, ARTS, SCIENCES

1839 2 de Fevereiro

THE LITERARY GAZETTE AND JOURNAL OF BELLES LETTRES, ARTS, SCIENCES   No. 1150   London, Saturday, february 2, 1839 pAG.72, 73, 74, 75

Fine arts. The new art.   the great sensation created by the new discovey in the fine arts, which our friends on the other side of the Channel have, with national and personal characteristicness, chosen to call Dagueroscope, but which our unpretending countryman, Mr. Talbot (rather than Talbotoscope), has dominated Photogenic, has induced us to bestow further attention upon the subject, which we had the pleasure of first making known to the public. What is done in the Litterary Gazette to-day will be important, as settling the claim to originality in regard to all parties concerned in this interesting discovery. The flavour of a letter from Mr. Talbot (a gentleman so justly honoured in the scientific circles), puts on record the unquestionable dates of his experiments ; and we have seen and examined the exquisit specimens which mark his progress and demonstrate his success. The statements are corroborated by the usual Reports from the Royal Institution and Royal Society; which we have not been anxious to give so much in detail, in consequence of our possessing Mr. Talbot’s own lucid and unassuming account of what he has achieved. In order to complete the matter, as far as present circumstances admit, we have also, at the risk of repetition, procured the most accurated details of M. Daguerre process, and the opinion of the French philosophers thereon. as he is recommended to be more secret than Mr. Talbot has been, in order that he may treat with government for his sufficient reward, we cannot, of course, speak more plaintly than the somewhat flowery descripition we have received enables us. But we think enough appears to render it palpable that there is a very considerable difference between the materials employed, themeans used, and theresults. Thus, at the Royal Institution, on Friday evening, were exhibited a variety of specimens of a process invented by Mr. Talbot, but which appears to differ from that of M. Daguerre, especially in this, that Mr. Talbot reverses the natural effect, representing dark objects light, and light objects dark. Different preparations of silver seem to be adopted – nitrate, chloruret, and probably others; but whoever attains the object most effectually, it is a generous rivalry, and will, we trust, be continued to the end. Mr. Talbot’s method of fixing his drawings, so that the sun can effect or alter them no more, is of the utmost value. His copying of engravings (there is a sweet one of Venice), by first getting them with the lights and shades reversed, but then copying from the reversed impression, as before, is singularly ingenious. Figures painted on glass are exquisitely rendered; and an oriel window of many feet square is reduced to a picture of two inches, in which every line is preserved with a minuteness inconceivable until seen by the microscope. At present we will not dilate any further on this memorable topic, but beg to suggest experiments with the hydro-oxygen powers of light, or such lights as Lieut. Drummond’s – and with this hint alone, request our reader’s attention to –   1.      Mr. Talbot’s Letter. 2.      The account of the French Invention. 3.      Report of the Royal Institution; and, 4.       Report of the Royal Society   PHOTOGENIC DRAWING. To the Editor of the Literary Gazette.   Dear Sir, - I have great pleasure in complying with the wish which you have expressed to me, that I would go into some details respecting the invention which I have communicated to the Royal Society; viz the art of photogenic drawing, or of forming pictures and images of natural objects by means of solar light. I do this the more readily, on account of the interest with which the scientific public have read the accounts which I have recently appeared respecting the discoveries of M. Daguerre, of Paris, in some respects identical with mine – in others, I think, materially different. Although I am very far indeed from being of the opinion, that,   “Chance rules supreme in the affairs of men;”   yet I cannot help thinking that a very singular chance (or mischance) has happened to myself, viz. that after having devoted much labour and attention to the perfecting of this invention, and having now brought it, as I think, to a point in which it deserves the notice of the scientific world, - that exactly at the moment when I was engaged in drawing up an account of it, to be presented to the Royal Society, the same invention should be announced in France. Under these circumstances, by the advice of my scientific friends, I immediately collected together such specimens of my process as I had with me in town, and exhibited them to public view at a meeting of the Royal Institution*([i]). My written communication to the Royal Society was, from its length, necessarily deferred to the week following *([ii]). These steps I took, not with the intention of rivalising with M. Daguerre in the perfection of his process (of which I know nothing, but am ready to believe all that Biot and Arago have stated in their praise),  but to preclude the possibility of its being said hereafter, that I had borrowed the idea from him, or was indebted to him, or any one, for the means of overcoming the principal difficulties. As the process of M. Daguerre is at present a profound secret, even at Paris, it is evident that no one could imitate him here, or exhibit formed in the same way, or depending on the same optical principles, who was not already fully acquainted with a secret, not, indeed, the same, but similar or tantamount to his. That M. Daguerre’s pictures will stand the effect of time, is, I suppose, the fact, though I do not find it expressly mentioned in the report of M. Arago (Comptes Rendus, 7th January). My own have stood between three and four years. I therefore consider that the principles of the art are firmly laid. Many instruments have been devised at various times for abridging the labour of the artist in copying natural objects, and for insuring greater accuracy in the design than can be readily attained without such assistance. Among these may be more particularly mentioned, the Camera Obscura and the Camera Lucida, which are familiar to most persons; certainly very ingenious and beautiful instruments, and in many circumstances eminently useful, especially the latter. Yet are there many persons who do not succeed in using them, and I believe that few are able to do so with great success, except those who, in other respects, are skilled in drawing. Up to certain point, these inventions are excellent; but beyond that point they do not go. They assist the artist in his work; they do not work for him. They do not dispense with his time; nor with his skill; nor his attention. All they can do is to guide his eye and correct his judgment; but the actual performance of the drawing must be his own. From  all these prior ones, the present invention differs totally in this respect (which may be explained in a single sentence), viz. that, by means of this contrivance, it is not the artist who makes the picture, but the picture which makes ITSELF. All that the artist does is to dispose the apparatus before the object whose image he requires: he then leaves it for a certain time, greater or less, according to circumstances. At the end of the time he returns, takes out his picture, and finds it finished. The agent in this operation is the solar light, which being thrown by a lens upon a sheet of prepared paper, stamps upon it the image of the object, whatever that may chance to be, which is placed before it. The very foundation of the art, therefore, consists in this – eminently curious – natural fact, viz. that there exists a substance so sensitive to light as to be capable of receiving even its faint impressions. The whole possibility of the processdepends upon this; for if no such substance existed in rerum natura, the notion of thus copying objects would be nothing more than a scientific dream. Moreover, it is not sufficient that the paper should be so sensitive asto receive the impressions of external objects; it is requisite also, that, having received them, it should retain them; and moreover, that it should be insensible with regard to other objects, to which it may be subesqently exposed. The necessity of this is obvious, for otherwise new impressions would be received, which would confuse and efface the former ones. But it is easier to perceive the necessity of the thing required than to attain to its realisation. And this has hitherto proved a most serious obstacle to those who have experimented with this object in view. This was one of the few scientific inquiries in which Sir Humphry Davy engaged, upon which Fortune did not smile. Either his inquiries took a wrong direction, or else, perhaps, the property sought for was of so singular a nature, that there was nothing to guide the search, or perhaps he despaired of it too soon; however this may be, the results undoubtedly was, that the attempt proved unsuccessful, and was abandoned. As Sir Humphry Davy himself informs us, “ No attempts have has yet been successful”. These words are quoted from his own account in the “Journal of the Royal Institution for 1802”. The  subject then dropped, and appears to have been no more spoken of for upwards of thirty years. When, in 1834, unaware of Davy’s researches, I undertooka course of experiments with the same object in view, I know not what good star seconded my efforts; but, after various trials, I succeeded in hitting upon a method of obtaining this desideratum. By this process, it is possible to destroy the sensibility of the paper, and to render it quite insensible. After this change it may be exposed with safety to the light of day; it may even be placed in the sunshine: indeed, I have specimens which  have been left an hour in the sun without having received apparent deterioration. A fact, therefore,is thus established which is not without its importance in a theorical point of view, besides its more immediate application to purposes of utility. With this kind of paper, eminently susceptible of being acted on by light, and yet capable of losing that property when required, a great number of curious performances may readily be accomplished. The most remarkable of these, is undoubtedly the copying the portrait of a distant object, as the façade of a building, by fixing its image in thr Camera Obscura; but one perhaps more calculated for universal use in the power of depicting exact facsimiles of smaller ojects which are in the vicinity of the operator, suchas flowers, leaves, engravings, &c., which may be accomplished withgreat facility, and often with  degree of rapidity that is almost marvellous. The Specimens of this art which I exhibited at the Royal Instituation, though consisting only of what I happened  to have with me in Town, are yet sufficient to give a general idea of it, and to show the wide range of its applicability. Among  them were pictures of flowers and leaves; a pattern of lace; figures taken from painted glass; a view of Venice copied from an engraving; some images formed by the Solar Microscope, viz. a a slice of wood very highly magnified, exhibiting the pores of two kinds, one set’much smaller than the other, and more numerous. Another Microscopic  sketch, exhibiting the reticulations on the wing of an insect. Finally: various pictures, representing the architecture of my house in the country; all these made with the Camera Obscura in the summer of 1835. And this I believe to be the first instance on record, of a house having painted its own portrait. A person unacquainted with the process, if told that nothing of all this was executed by the hand, must imagine that one has at one’s call the Genius of Aladdin’s Lamp. And, indeed, it may almost be said, that this is something of the same kind. It is a little bit of magic realized: - of natural magic. You make the powers of nature work for you, and no wonder that your work is well and quickly done. No matter whether the subject be large or small, simple or complicated; whether the flower-branch which you wish to copy contains one blossom or one thousand; you set the instrument in action, the allotted time elapses, and you find the picture finished, in every part, and in every minute particular. There is something in this rapidity and perfection of execution, which is very wonderful. But after all, what is Nature, but one great field of wonders past our comprehension? Those, indeed, which are every-day occurrence, do not habitually strike us, on account of their familiarity, but they are not the less on that account essential portions of the same wonderful Whole. I hope it will be borne in mind by those who take an interest in this subject, that in what I have hitherto done, I do not profess to have perfected an Art, but to have commenced one; the limits of which it is not possible at present exactly to ascertain. I only claim to have based this new Art upon a secure foundation: it will be for more  skilful hands than mine to rear the superstructure. – I remain, dear Sir, Yours, &c. H. FOX TALBOT 44 Queen Anne Street, January 30, 1839     FRENCH DISCOVERY. – PENCIL OF NATURE.   Who has not admired the splendid and wonderful representations in the camera obscura? – images so clear, so full of life, so perfectly representing every object in nature. These living pictures, by traversing: the lens and mirrors, are thrown down with double beauty on the table of the camera obscura, by the radiant finger of light. The new “art” has been discovered to fix these wonderful images, which have hitherto passed away volatile – evanescent as a dream – to stop them at our will, on a substance finely sensible to the immediate action of light, and render them permanent before our eyes, in traces represented by tints in perfect harmony on each point, with different degrees of intensity. We must not, however, believe, as he has been erroneously reported to the public, with respect to these [Parisian] experiments, that the proper colours of the objects are represented, in these images, by colours they are _______([iii])represented with extreme truth, by light, and every gradation of shade;- as an oil-painting is given by a perfect engraving, consisting of black lines; or, perhaps, more akin to a design made with mathematical accuracy, and in aqua tinta; for there are no crossings of lines in the designs by the pencil of nature. Red, blue, yellow, green, are rendered by combinations of light and shade; by demi-tints, more or less clear or obscure, according to the quantity of light in each colour. But in these copies, the delicacy of the design – the purity of the forms – the truth and harmony of tons – the aerial perspective – the high finish of the details, are all expressed with the highest perfection. The formidable lens, which often betrays monstrosities in the most delicate an aerial of our master-pieces, may here search for defects in vain. The creations of nature triumph. Far from betraying any defect, the highest magnifier only trends to show more clearly its vast superiority. At each step, we find new objects to admire, revealing to us the existence of exquisite details, which escape the naked eye, even in reality. Nor can this astonish us when the radiant light, which can only act according to the immutable laws of nature, substitutes its rays for the hesitating pencil of the artist. M. Daguerre has represented, from the Pont des Arts, and in a very small space, the whole of the magnificent buildings on the right bank of the Seine, including that part of the Louvre containing the grand gallery of pictures. Each line, each point, is rendered with a perfection quite unattainable by all means hitherto used. He has also reproduced the dark mass of Nôtre Dame, with its immense draperies and Gothic sculptures. He has also taken the view of a building, in the morning at eight o’clock, at mid-day, and at four o’clock in the afternoon, during rain, and in sunshine. Eight or ten minutes at most, in the climate of Paris, is sufficient; but, under a more ardent sun, such as that of Egypt, one minute will suffice. To artists and savans who travel, and who often find it impossible to prolong their stay at interesting places, this process must be most welcome. The French journals, and reports of proceedings, however, admit that these admirable representations still leave something to be desired as to effect, when regard as works of art. It is singular, they observe, that the power which created them seems to have abandoned them; and that these works of light want light. Even in those parts the most lighted, there is an absence of vivacity and effect; and it is allowed, that amidst all the harmony of their forms, these views appear subjected to the sober and heavy tone of colour imported by a dull northern sky. It would appear, that by passing through the glasses of the optical arrangement of M. Daguerre, all the views are uniformly clothed with a melancholy aspect, like that given to the horizon by the approach of evening. Motion, it is obvious, can never be copied; and the attempt to represent animals and shoeblacks in action, consequently failed. Statuary is said to have been well defined; but, hitherto, M. Daguerre has not succeeded in copying the living physiognomy in a satisfactory manner, though he does not despair of success. It could not have escaped chemists, that various chemical products are sensibly affected by light. Some gases may remain together in the dark, without any effects, but a ray of light will cause instant explosion. Other bodies, such as the chloruret of silver, are modified in colour. It at first takes a violet tint, afterwards becomes black. This property would doubtless, have suggested the idea of applying it to the art of design. But, by this method, the most brilliant parts of the object become discoloured, and the darker parts remain white: this produces an effect contrary to the fact. And again, the continued action of light tends to render the whole dark. Mr. Talbot’s method would seem to be based on the use of the salts of silver, with the addition of some substance, or covering, to prevent the further action of light, after the design was complete. This discovery will doubtless make a great revolution in the arts of design; and, in a multitude of cases, will supersede old methods altogether inferior. The temporary interest of many may, at first, be affected; but whatever has the true character of good, cannot essentially do mischief. The invention of printing soon gave employment to many more than were employed as copyists. Even in our own time, the substitution of steel-plates for engraving, instead of copper, although fifty times as many copies may be taken from them, has, by the substitution of good engravings for indifferent ones, so extended the demand, that more steel-plates are now required were formerly used of copper. We must add a few words with reference to science. This newly discovered substance, so easily acted upon by the rays of light, opens a wide field for photometric experiments, which hitherto have been hopeless, more particularly on the light of the moon. M. Arago recalls to our attention some experiments made by himself, jointly with other philosophers, by which the light of the moon (300,000 times less than that of the sun), concentrated by the most powerful glasses, gave no indication of chemical action on the chloruret of silver, nor any sign of heat on the most delicate thermometer. We should be glad to know if any experiments have yet been made with the concentrated light of the moon on the thermo-electrical apparatus, which may be constructed of extreme delicacy. The substance used by M. Daguerre is evidently sensible to the action of lunar light, since, in twenty minutes, he can represent under the form of a white spot, the exact image of this luminary. M. Biot, who, from the nature of his labours in the fields of science, takes a lively interest in the discovery in question, and anticipates much from the means afforded by it to carry out the analysis of some of the most delicate phenomena of nature. M. Daguerre has, it is asserted already discovered some new properties of light, and is still carrying on the investigation. ___________________ ROYAL INSTITUTION FRIDAY, 25th Jan. – Mr. Woodward “On a new Apparatus for the Public Demonstration of the General Properties and Laws of the Polarization of Light”. After a brief outline of the undulatory theory of light, Mr. Woodward proceeded to exhibit  with the old oxy-hydrogen apparatus, fitted with lenses, the splendid  phenomena of polarized light, using tourmaline as the analysing plate. The new apparatus (Godar’s) with which he also illustrated nearly the whole phenomena, is of a more simple construction, and much cheaper. The light is polarized by plate glass; for the expensive tourmaline, mica is substituted; and for the lens, a metallic reflector. This arrangement will tend much to make more generally known the beautiful wonders of this important science. At the conclusion of the lecture, Mr. Faraday directed attention to drawings in the library, sent there by H. F. Talbot, F.R.S., and by him named “Photogenic Drawings”. They were of the same character as those of M. Daguerre. The two processes, he observed, of M. Daguerre and of Mr. Talbot, effecting the same objects, may be different, or may be the same. As yet neither is know; and each has been perfected by two scientific experimenters in different countries, without a knowledge of each other’s pursuit. The principal object of the exhibition of the photogenic drawings, on this occasion, was meant (as was understood) to establish a date, in order, that should M. Daguerre’s discovery be made public previously to the reading, before the Royal Society, of Mr. Talbot’s paper detailing his process, no charge of imitation could be brought against Mr. Talbot, in case of identity of process. And that each discovery should be thus proved to be original. No human hand has hitherto traced such lines as these drawings displayed; and what man may hereafter do, now that dame Nature has become his drawing mistress, it is impossible to predict.    ROYAL SOCIETY   Mr. LUBROCK in the chair. – A highly interesting paper by Henry Fox Talbot, Esq. was read. It detailed the author’s discovery upwards of five years ago, of the new process of delineating objects. From the first volume of the Journal of the Royal Institution, it appears that the late Mr. Wedgewood had some idea of the discovery; that ingenious gentleman, in conjunction with Sir H. Davy, made many experiments, but they found all their endeavours to obtain success ineffectual: so much so, that is discouraged them, and would have discouraged the author of the present memoir had he read the remarks of Sir H. Davy, contained in the Journal alluded to, prior to the experiments which ultimately led to his invention. At first it consisted in laying the nitrate of silver on paper, and by the means of the camera obscura and the solar ray acting on the paper, a perfect impression is obtained, of any object in half a second; it was found, however, that the image thus obtained, by exposure to the light faded, and after awhile disappeared. By repeated experiments, and the most devoted attention, Mr. Talbot, by what he calls sensitive paper (a great improvement upon that which he originally employed), has overcome this great drawback; pictures he has had in this possession for years are now as vivid as they were when first produced. The image obtained is white, but the ground is beautifully coloured, and readily obtainable, either sky-blue, yellow, rose-colour, or black, - green is excluded; these variations of colour Mr. Talbot considers as so many chemical compounds. Objects the most minute are obtained, - the delicate hairs on the leaves of plants, - the most minute and tiny bivalve calyx, - nay, even a shadow, the emblem of all that is most fleeting in this world, is fettered by the spell of the invention, and remains perfect and permanent long after it has been given back to the sunbeam which produced it; in short, to use Mr. Talbot’s own words, the picture is “ended as soon as begun”. The extend of the value of this invention cannot at present be anticipated; already the author  has applied it with perfect success to the copying of sculpture, engravings, hand-writing: and in every case so complete has been the image, that is has been mistaken for the original. The value of it even now to naturalists and others travelling abroad, many of whom are ignorant of drawing, must be immense. Lord Brougham was present, and paid profound attention to Mr. Talbot’s paper.

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([i])*Both noticed elsewhere.

([ii])*Both noticed elsewhere.

([iii]) Palavra ilegível no exemplar de THE LITERARY GAZETTE AND JOURNAL OF BELLES LETTRES, ARTS, SCIENCES a que tive acesso (Nota minha).