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of his darkened chamber, all but the one he face, the part concealed by it remains wishes to perpetuate, and he can thus ex- white, and the other parts speedily become hibit and fix in succession all those floating dark. For copying paintings on glass, the images and subtle forms which Epicurus solution should be applied on leather, and fancied, and Lucretius sang.

in this case it is more readily acted upon The art of Photography, or that of deli- than when paper is used. After the color neating objects by the agency of the light has been once fixed upon the leather or which they radiate or reflect, is substan- paper, it cannot be removed by the applitially a new invention, which we owe to cation of water, or water and soap, and it two individuals, Mr. Talbot and M. is in a high degree permanent." Daguerre, although, like all other arts, Mr. Wedgewood endeavored by repeated some approximation had been made to it washings, and by thin coatings of fine varby previous inquirers. So early as 1802, nish, to prevent the white parts of his picMr. Thomas Wedgewood, the celebrated tures from becoming dark when exposed to porcelain manufacturer, published in the light; but all his attempts were fruitless, Journals of the Royal institution, A me- and he was obliged therefore either to exthod of copying paintings upon glass, and hibit them in candle-light, or for a short of making profiles by the agency of light time in the shade. This process was apupon nitrate of silver, which was accompa- plied by its author to taking profiles, and nied with some observations by Sir Hum- " making delineations of all such objects as phry Davy. Having ascertained that are possessed of a texture partly opaque white paper or white leather, moistened and partly transparent, such as the woody with a solution of nitrate of silver, under- fibres of leaves and the wings of insects.” goes no change when kept in a dark place,” He tried also, but without much success, but "speedily changes color” when “ex- to copy prints; and he failed still more sigposed to the daylight,” Mr. Wedgewood nally in what was his leading object, to found “that the alterations of color took copy the images in the camera-obscura. In place more speedily in proportion as the following these processes, Sir H. Davy light was more intense ;' that the full ef- found“ that the images of small objects fect was produced by the sun's light in two produced by means of the solar microscope, or three minutes, whereas two or three may be copied without difficulty on prehours were required in the shade; that the pared paper-the paper being placed at red rays have little action upon it, the yel- but a small distance from the lens ;' and low and green more, and the blue and vio- he ascertained that about 1 part of nitrate let most of all. “Hence,” says Mr. to about ten of water, gave the best soluWedgewood," when a white surface cover- tion. Mr. Wedgewood likewise ascertained with a solution of nitrate of silver, is ed that the muriate was more susceptible placed behind a painting on glass exposed than the nitrate of silver, and that both to the solar light, the rays transmitted were most readily acted upon while wet. through the differently painted surfaces, He impregnated his paper with the muriproduce distinct tints of brown or black, ate, either by diffusing it through water, sensibly differing in intensity, according to and applying it in this form, or by imthe shades of the picture, and where the mersing paper moistened with the solution light is unaltered the color of the nitrate of the nitrate in very diluted muriatic acid. becomes deepest. When the shadow of The impossibility of removing the coloring any figure is thrown upon the prepared sur- froni the white parts of the pictures, sug

gested to Mr. Wedgewood the idea tha * Dico igitur, rerum effigias, tenuisque figuras Mittier ab rebus summo de corpore earum;

a portion of the metallic oxide abandons Quæ quasi membrana, vel cortex nominitanda'st?lits acid to enter into union with the aniQuod speciem, ac formam similem gerit ejus mal or vegetable substance, so as to form Imago,

with it an insoluble compound,” and he had Quojuscunque cluet de corpore fusa vagari.

experiments in view to discover some subNext, for 'tis time, my muse declares and sings

stance that could destroy this compound What those are we call images of things, Which like thin films from bodies rise in streams,

either by simple or complicated affinities. Play in the air and dance upon the beams.- “Nothing," he adds, but a method of A stream of forms from every surface flows, preventing the unshaded parts of the deliWhich may be called the film or shell of those, neation from being colored by exposure to Because they bear the shape, they show the frame And figure of the bodies whence they came. the day, is wanted to render the process as CREECH

useful as it is elegant."

This beautiful process, which, notwith-them with iodine of potassium greatly distanding its defects, it required neither luted with water ; but the method which he science nor skill to repeat, seems to have proposed, as being safer and simpler, was excited no interest whatever. The writer to immerse the picture in a strong solution of this Article gave a notice of it in a Scot- of common salt, and then to dry it after tish Journal, so early as 1803, but he has wiping off the superfluous moisture. not been able to learn that the experiment At this period Mr. Talbot's pictures of Mr. Wedgewood was repeated. With were negative, like those of Mr. Wedgeout knowing what had been done by wood, but yet he has distinctly shown how Mr. Wedgewood, Mr. Henry Fox Tal-positive pictures, or those in which the bot, of Lacock Abbey, was led by acciden- lights and shades are given as in nature, tal circumstances to turn his attention to may be obtained. the subject of giving a permanent existence to those beautiful but evanescent pic- “In copying engravings," says Mr. Talbot, tures, which the camera-obscura presents " by this method, the lighis and shadows are to our view. Recollecting that nitrate of reversed, consequently the effect is wholly altered. silver was changed or decomposed by light, (fixed) so as to bear sunshine, it may be after

But if the picture so obtained is first preserved he began, early in 1834, that series of experiments which led him to the beautiful and by means of this second process the lights and

wards itself employed as an object to be copied, art which now bears his name. Anxious shadows are brought back to their original disposito perfect the new art which he had disco-tion. In this way we have indeed to contend with vered, Mr. Talbot continued his experi- the imperfections arising from two processes in, ments till the year 1839, when he commu

stead of one; but I believe this will be found nicated to the Royal Society Some Ac- merely a difficulty of manipulation."* count of the Art of Photogenic Drawing, or the process by which natural objects may be

The communications of Mr. Talbot to made to delineate themselves without the aid the Royal Society could not fail to draw the of the artist's pencil. In this paper, which attention of philosophers to so curious an art, was read to the Society on the 31st Janu- and we accordingly find that the Rev. J. B. ary, 1839, several months before M. Da- Reade, F.R.S., a gentleman to whom the sciguerre had published his photogenic pro

ences owe valuable obligations, had made imcesses, Mr. Talbot enumerates the various portant additions to the photogenic processpurposes to which the new art could be es, and had himself applied them to the deliapplied; but it was not till the 21st Feb- neation of objects of natural history, of ruary that he communicated to the Society

which he took pictures by the solar microhis process for preparing the paper, and his scope. The following process was commu

, method of fixing the images. A sheet of nicated by Mr. Reade, on the 9th of March, superfine writing paper (of a good firm 1839, to E. W. Brayley, Esq., who exquality and smooth surface) is dipped into plained the process and exhibited the a weak solution of common salt (muriate drawings referred to, at one of the soirées of soda) and wiped dry. A solution of of the London Institution on the 10th April,

1839. nitrate of silver, namely, a saturated solution six or eight times diluted with water,

“ The more important process, and one prois spread with a brush over one surface bably different froi, any hitherto employed, cononly, and the paper when dry is fit for use. sists in washing good writing paper with a strong When leaves of flowers, lace, engravings, solution of nitrate of silver, containing not less &c., are laid upon the nitrated surface of than 8 grs. to every drachm of distilled water. the paper and exposed to the sun, very

thus prepared is placed in the dark, and perfect images of them are obtained, the allowed to dry gradually. When perfectly dry, lights and shades being reversed, or, what sion of galls prepared according to the Pharmaco

and just before ii is used, I wash it with an infu. is the same thing, the pictures are deline- pæia, and immediately, even while it is yet wet, ated by white in place of black lines, or are ihrow upon it the image of microscopic objects by negative pictures. In like manner, the means of the solar microscope. pictures thrown upon the nitrated paper " It will be unnecessary for me to describe the placed in the focus of a camera-obscura are effect, as I am able 10 illustrate it by drawings thus negatively delineated. In order to fix produced. I will only add, with respect to the these pictures, or prevent the white lines time, that the drawing of the flea was perfected in and portions from being blackened by ex

* London and Edin. Phil. Mag. March, 1839. posure to light, Mr. Talbot first washed / No. 88, vol. xiv., p. 208.

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less than five minutes, and the section of cane, and ture (and without the water-mark), and the spiral vessels of the stalk.of common rhubarb, wash one side of it, by means of a soft in about eight orj ten minutes. These draw.

camel's-hair brush, with a solution comings were fixed by hydrosulphite of soda. They may also be fixed by immersing them for a few posed of 100 grains of crystallized nitrate minutes in weak sali and water, and then for the of silver dissolved in 6 oz. of distilled water, same time in a weak solution of hydriodate of po- having previously marked with a cross the tash. The drawing of the Trientalis Europea side which is to be washed. When the was fixed by the latter method : it was procured in paper has been dried cautiously at the fire, half a minute, and the difference in the color of or spontaneously in the dark, immerse it for the ground is due to this rapid and more powerful action of the solar rays. This paper may be suc

a few minutes (two minutes at a temperacessfully used in the camera obscura.

ture of 65°) in a solution of iodide of po“Further experiments must determine the na. tassium, consisting of 500 grains to one ture of this very sensitive argentine preparation. I pint of distilled water. The paper is then presume that it is a gallate or tannate of silver, and, to be dipped in water, and then dried by if so, it will be interesting to you to know that applying blotting paper to it lightly, and what has hitherto been looked upon as a common afterwards exposing it to the heat of a fire, chemical compound is produced or suspended at

The pleasure by our command over the rays of light." or allowing it to dry spontaneously.

paper thus prepared is called iodized paper, This process cannot fail to be considered and may be kept for any length of time in as highly honorable to the ingenuity of Mr. a portfolio not exposed to light. When a Reade. The first public use of the infusion sheet of this paper is required for use, wash of nut-galls, which, as we shall see, is an it with the following solution, which we essential element in Mr. Talbot's patented shall call No. 1,--take 100 grains of nitrate process, appears to be due to Mr. Reade, of silver dissolved in two ounces of distilled and his process of fixing his pictures by water, and add to this one-third of its vohyposulphite of soda, which has since been lume of strong acetic acid. Make another universally used as the best, and was after- solution, No. 2, by dissolving crystallized wards suggested in 1840 by Sir John Her- gallic acid in cold distilled water, and then schel, must be regarded as an invaluable ad- mix the two solutions together in equal prodition to the photographic art.

portions, and in no greater quantity than is Notwithstanding the great beauty of the required for immediate use, as it will not drawings which Mr. Talbot obtained by the keep long without spoiling. This mixture, process which he published, the art was still called gallonitrate of silver by the patentee, far from being perfect. The discovery of is then to be spread by a soft camel's-hair a paper highly sensitive to light was essen- brush on the marked side of the iodized tially necessary to the production of por- paper, and after allowing the paper to retraits from the life, and even of accurate main half a minute to absorb the solution, pictures of buildings and landscapes, in it should be dipped in distilled water and which the lights and shadows are constant- dried lightly, first with blotting paper, and ly changing both from the motion of the then by holding the paper at a considerable sun and of the clouds. Mr. Talbot accord- distance from a fire. When dry the paper ingly directed himself anew to this part of is fit for use, and it is advisable to use it his subject, and he succeeded beyond his within a few hours. most sanguine expectations. He discovered The paper thus prepared is highly sensia process by which paper could be made so tive to light, and it must now be placed in sensitive that it was darkened in five or six the camera-obscura in order to receive on seconds when held close to a wax candle, its marked surface a distinct image of the and gave impressions of leaves by the light landscape or person whose picture is reof the moon.

quired. After remaining in the camera To this most important invention Mr. from 10 seconds to several minutes, accordTalbot gave the name of Calotype, which ing to the intensity of the light, it is taken his friends have now changed into the more out of the camera in a dark room. If the appropriate name of Talbotype, and he se object has been strongly iHuminated, or if cured the exclusive privilege of using it by the paper has been long in the camera, & . a patent for England, which was sealed on sensible picture will be seen on the paper; the 8th February, 1841. The following but if the time of exposure has been short, is the patent process for obtaining the nega- or the illumination feeble, the paper will tive picture :-Take a sheet of paper with appear entirely blank.” An invisible a smooth surface and a close and even tex-l image, however, is impressed on the paper,

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and may be rendered visible by the follow-process; but though it has the advantage of ing process :-“ Take some of the gallo- giving sharper lines than the double process, nitrate of silver, and with a soft camel's- it is greatly inferior to it, and is not likely hair brush wash the paper all over with this ever to come into general use. All the liquid, then hold it before a gentle fire, and copies of pictures which it yields are rein a short time the image will begin to ap- versed, and all its portraits and landscapes pear, and those parts upon which the light reversed; but the principal objections to its has acted most strongly will become brown use are two : It requires such a length of or black, while the others remain white. time that portraits could not easily be taken The image continues to grow more and by it, and even when we do obtain a good more distinct for some time, and when it picture, we cannot multiply it as in the becomes sufficiently so the operation must double process. be terminated, and the picture fixed. In The following is the single process, as order to effect this the paper must be dipped, contained in Mr. Talbet's specification :first into water, then partly dried by blotting paper, and afterwards washed with a “ A sheet of calotype paper is exposed to the solution of bromide of potassium, consisting daylight for a few seconds, or until a visible disof 100 grains of the salt dissolved in 8 or coloration or browning, of its surface takes place; 10 ounces of water. The picture is then then it is dipped into a solution of iodide of potasfinally washed in water and dried as before. sium, consisting of 500 grains 10 one pint of water.

This visible discoloration is apparently removed In place of bromide of potassium a strong by the immersion ; such, however, is not really the solution of common salt may be used.case, for if the solution was dipped into a solution

By this process we get a negative picture, of gallo nitrate of silver, it would speedily blacken and from it any number of positive pictures all over. When the paper is removed from the may be obtained in the following manner :

iodide of potassium, it is washed with water, and Dip a sheet of good paper in a solution of then dried with blotting paper. It is tnen placed

in the camera obscura, and after five or ten common salt, consisting of one part of a minutes it is removed therefrom, and washed with saturated solution to 8 parts of water, and gallo-nitrate of silver, and warmed as before directdry it first with blotting paper, and then ed. An image of a positive kind is thereby prospontaneously. Mark one of its sides, and duced, and represents the lights of objects by wash that side with a solution of nitrate of lights, and the shades by shades, as required.” silver, which we shall call No. 3, consisting of 80 grains of salt to 1 oz. of distilled The property of hydriodate of potash, to water. When this paper is dry, place it whiten paper that has been darkened by with its marked side uppermost on a flat exposure to light, was observed about the board or surface of any kind, and above it same time by Mr. Hunt, Dr. Fyfe, Sir J. put the negative picture, which should be Herschel, Mr. Talbot, and M. Lassaigne. pressed against the nitrated or positive Mr. Hunt, in particular, has paid much atpaper by means of a glass plate and screws. tention to the photographic processes In the course of 10 or 15 minutes of a bright founded upon this peculiarity of the hydriosunshine, or of several hours of common day-date, and has published the results of his light, a fine positive picture will be found inquiries in a very interesting paper, which on the paper beneath the negative picture. appeared in the Philosophical Magazine When this picture has been well washed or for September, 1840. He has more resoaked in water, it is washed over with a cently resumed the subject in his very

valusolution of bromide of potassium already able and interesting volume, entitled, Rementioned, or plunged in a strong solution searches on Light, and has there given an of common sali.

explanation of the best method of preparAs all the inequalities and imperfections ing a good photographic paper," on which,

, of the paper on which a negative picture is by the united agency of the hydriodate and formed, are copied on the positive picture the solar rays, perfect pictures may be prowhich it yields, attempts have been made duced in the camera or otherwise, having to obtain positive pictures by a single pro- their lights and shadows correct as in nacess. This was first effected by Dr. Fyfe, ture. This branch of photography is of King's College, Aberdeen, and M. Las- more curious than useful ; for though the saigne of Paris; and Mr. Talbot has in- pictures may be perfectly fixed, and retain cluded a process of this kind in his specifi- their color as long as they are kept in a cation. We have in our possession one of portfolio, and but occasionally exposed to the pictures taken by Mr. Talbot by this sun-light, yet, when they are occasionally

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kept in the light, and exposed to the free and a deoxydizing agent. As a still further action of the atmosphere, they gradually simplification of his process, Mr. Talbot fade, and in the course of a few weeks not a washes iodized paper with a mixture of 26 trace of the picture is to be seen.

parts of a saturated solution of gallic acid, Various photographic processes, under va- and one part of the ordinary solution of nirious names, such as the Cyanotype, the Si- trate of silver. It may then be dried withderotype, the Chrysotype, the Energiatype, out the fear of spoiling, may be kept a litthe Platinotype, the Aurotype, the Chroma- tle time, and used without further preparatype, the Catalysotype, have been described tion. by different authors; but notwithstanding the In order to improve photographic drawingenuity which they display, and the beauty ings, Mr. Talbot keeps them twice the of the results which some of them yield, they usual time in the sun, so that the shadows are all of inferior' value to the Talbotype, are too dark, and the lights not white. which, though it has been rendered more The drawing is then washed, and plunged perfect since its first publication, by Mr. for one or two minutes in a solution of Talbot himself and by other philosophers— iodine of potassium, of the strength of 500 and is doubtless still susceptible of further grains to a pint of water. * It is then improvement--will, we are persuaded, con- washed, and plunged into a hot bath of tinue to be the favorite photographic pro- hyposulphite of soda, till the proper tints cess, when the sun.pictures are to be receiv- are obtained. Mr. Talbot also improves ed on paper. We shall therefore confine his positive pictures by waxing them, and ourselves to this valuable form of the art, placing white or colored paper behind and give our readers some account of the them.f improvements which it has received since Various changes and some improvements Mr. Talbot's first specification appeared

have been made upon the

processes adoptThe earliest improvements upon the Ca-ed by Mr. Talbot. Mr Hunt has given us

. lotype process, as given in Mr. Talbot's the following account of some of these :first patent, were made by Mr. Talbot himself, who secured his exclusive use of them

“ Mr. Channing of Boston appears to have by a second patent, which was sealed on the been the first to publish any method by which 1st June, 1843. In order to remove the gentleman directs that the paper be washed over

the calotype process could be simplified. This yellow tint from the negative picture, Mr. with sixty grains of crystallized nitrate of silver Talbot plunges it for ten minutes in an al- in one ounce of water, and when dry, with a somost boiling solution of hyposulphite of lution of ten grains of the jodide of potassium soda, in ten times its weight of water. in one ounce of water. It is then to be washed with When washed in warm water and dried, the water, and dried between blotting papers. It is now picture is placed upon a hot iron, and wax

fittor use. A paper of a mor esensitive kind is stated melted into the pores of the paper, to mixed solution of five grains of the jodide of potas

by the same authority, be prepared by using a increase its transparency. Mr. Talbot sium, and fivegrains of the chloride of sodium in an also recommends that a warm iron be plac-ounce of water. My own experience enables me to ed behind the calotype paper while in say that but little, if any, improvement can be made the camera to increase its sensibility. In order to simplify the process by dispen- the negative pictures is essentially necessary to

* The removal of every portion of iodine from sing with the second wash, Mr. Talbot their giving numerous copies. “This arises," says washes the iodized paper with gallic acid, Mr. Talbot," from the chemical fact, thai solar and thus obtains io-gallic paper,

light and a minute portion of iodine, acting together quires only to be washed with the solution (though neither of them separately), are able to de

compose the oride of silver, and form a colorless of nitrate of silver, before it is put into the jodiđe of the metal.”—Pencil of Nature, No. VI., camera. The picture, though generally in- Plate xxiv. visible, rapidly developes itself when remov- method of Photographic printing, and of Photo

† Mr. Talbot bas included in his second patent, a ed from the camera, requiring no further graphic publication. Letters are cut out of a transcare than ultimately to fix it. “ Instead of parent page and sorted, they are then put up in gallic acid,” Mr. Talbot observes, “ sul words, cemented, and copied photographically; and phate of iron answers the same purpose per- drawings on papers prepared with salt (3 or 4 oz. to

in Photographic publication he makes good negative fectly.” He mentions, also, that Tannin, 1 gallon of water) and the ammonio-nitrate of silver and other substances, such as tea, may be (50 grains of nitrate to 1 oz. of water, ammonia substituted for gallic acid, and he defines being added to form a precipitate, and redissolving the Calotype and Talbotype process as de- fixed them he takes positive drawings from the ne

the same, leaving the solution clear), and having pending on a combination of iodine, silver, gative copies as usual.

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