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placed in a vessel or square trough of sheet one-half of the spectrum, viz. the blue and copper, containing either a saturated solu- violet half, had alone the power of exciling tion of common salt, or a weak solution the iodine, in forming the picture; and that of hyposulphite of soda. The coating the other half, though destitute of the of iodine will thus be dissolved, a result power of excitation, had the property of which will be obtained when the yellow continuing the action of the blue and violet color has quite disappeared, and we have rays after they had produced a slight effect. only to pour over it distilled water, hot but Hence he shortened the time of sitting for not boiling: The drops of water which re- a portrait, by keeping it in the camera for main on the plate must be removed by a very short time, and competing the action blowing upon them. The picture thus by making the sun's light pass through a finished is then preserved from dust by red głass, and shine upon the plate for a placing it in a square of strong pasteboard few minutes. This process, however, was and covering it with glass; and if the ope- not suited to the professionał artist, and we ration has been successfully performed, we believe is not now practised. M. Claudet's shall have a picture almost as perfect in its invention could not fail to supersede it. details as that in the camera-obscura itself, He discovered that the sensitiveness of the though without any of the colors of nature. iodized plate was increased in a very reThe palette of the sun contains only a sin- markable degree by the action of the gle color, and that is white. The shades chloride of iodine or bromine, and when the in its picture are supplied by the black plate, before it had acquired the appearpolish of the metallic surface. When this ance of a yellow tint, was held, for about specular surface reflects a luminous object, two seconds, over the mouth of a bottle the white vapor of the mercury appears in containing either of these chlorides, the shade, and we thus obtain from the Daguer-vapor spread itself over the iodine film, reotype plate either a positive or a negative which soon acquired the proper yellow picture, according to the light in which it is color when placed in the iodine box. Vaviewed.

rious methods of applying these acceleratIf we judge of an art by the beauty of ing substances have been employed. M. its productions, we can scarcely deny that Fizeau exposes the iodized plate for a few the Daguerreotype, as applied to landscapes seconds to a very dilute solution of bromine and inanimate objects, came almost perfect in water, while others fill a vase with the from the hands of its inventor. The time vapor of bromine and chlorine by means of of exposure in the camera was too long to a syringe, which shall just contain as much make it applicable to the delineation of vapor as will coat the plate. The acceleliving objects; and though M. Arago re- rating power of the Jodine or Bromine marked, " that a very slight advance be- vapor was so great, that M. Claudet obyond his present progress will enable M. tained with it pictures in ten seconds, Daguerre to apply his processes to the execu- which would have required four or five tion of portraits from life," yet the accele- minutes by the original preparation of ration of the process, and the successful Daguerre. A new and very ingenious delineation of the human form, were effect-method of giving sensibility to the iodized ed by the genius of other artists. The plate, has been recently proposed by Mr. first portrait from life taken by the Daguer- Bingham. In order to avoid the use of reotype was taken on the 6th October, 1839, water for dissolving the bromine, he comby Mr. Walcott of New York, upon a bines bromine with hydrate of lime, and plate about the size of a sixpence, now in forms a sort of bromide of lime. This the possession of Mr. Johnson of that city, may be done by allowing bromine vapor to and portraits were afterwards taken by act upon hydrate of lime for some hours, or Messrs. Draper, Mapes, Johnson, and others. more conveniently by placing some of the

The art of taking portraits has been par- hydrate at the bottom of a flask, and then ticularly studied, and brought to a high putting some of the bromine into a glass degree of perfection, by M. A. Claudet, capsule, supported a little above the lime, who was the first person who discovered, the lower part of the flask being placed in in the beginning of May, 1841, an easy and water of the temperature of about 50° sure method of accelerating the action of The lime gradually becomes scarlet, like light upon the film of iodine, and thus the red iodide of mercury. By slightly greatly shortening the process. M. Ed-coloring the silver plate with the chloromund Becquerel had, indeed, shown that I iodide,

and then exposing it for a proper

known."*

time over the bromide of lime, Mr. Bing-receives from these accelerating substances, ham says that pictures may be obtained in a they have not yet enabled the photografraction of a second, even late in the after-pher to carry on his pursuits with artificial noon! The accelerating American mixture, light. Dr. Draper indeed obtained an imprepared by Mr. Walcott, viz. chlorine perfect picture of the moon by the aid of a combined with bromine, and the Hungarian Iers and a heliostate in balf an hour, upon mixture of M. Guerin, which is a compound an iodized plate. In fifteen seoonds the of bromine, chlorine, and iodine, may be Aame of a gas-light gave a distinct stain to obtained in the solid state by a combina- his plate, when held close to it, and in one tion with lime, like the bromine color; but minute the impression was strong. A gasMr. Bingham greatly prefers the pure bro- lamp gave a good representation of a figure mide of lime as the quickest accelerator yet on a magic lantern's slide, and with Drum

mond's light, and the Pea light of the oxySoon after M. Claudet's discovery of the hydrogen blow-pipe, he obtained the same accelerating property of the chlorides of result. Mr. Talbot has found that his seniodine and bromine, M. Gaudin of Paris sitive paper darkened when held five or six tried the bromide of iodine without chlo- seconds close to a wax candle, and it was so rine, and this compound is now generally distinctly acted upon by the light of the employed by photographers as highly sen- moon, that he took impressions of leaves upsitive, and producing the very best results. on it by moonlight. In 1841, Mr. Goddard When this compound of iodine and bro- obtained images of busts by gas-light, and mine is correctly prepared, it is of little by the oxyhydrogen light. Mr. Hunt made consequence whether the plate be exposed a similar experiments, and M. Claudet took shorter or a longer time to its vapor, which portraits from nature by the oxyhydrogen is not the case when they are applied sepa- light in fifteen or twenty seconds, with an rately. With the bromide of iodine the object glass of short focus; and his owa portwo ingredients evaporate in due propor- trait thus taken, was publicly exhibited "He tion, and provided neither of them be in obtained also impressions of black lace by excess on the plate, the coating will possess the light of the full moon in two minutes. its highest degree of sensibility.

He likewise obtained an image of the moon The following accelerating solution, which in his camera in four seconds, in which the has been kindly communicated to us by its shadowed parts of the disc were visible, and author, Dr. Karsten of Berlin, not only in about the same time the image of an alaimparts a high degree of sensitiveness to baster figure by the light of a candle in fifthe iodine film, but gives a fine color to the teen minutes, and a similar image by an picture. Make a saturated solution of bro- Argand lamp in five minutes. Mr. Kilburn anine, or equal parts of fuming nitric and has more recently obtained well-defined muriatic acids, and then add as much iodine photographic impressions by the light of as the solution will dissolve. As the iodine a common dip candle in ten minutes, by the enables the liquid to dissolve more bremine, smallest fish-tail burner of coal gas in three add as much more as it will dissolve. After minutes, and by an oil lamp (å selar one) this addition it will dissolve more iodine, in the same time. and so on, till the solution is completely Next in importance to the acceleration of saturated with both these bodies. In this the photographic process is the perfection of concentrated solution the bromine and the image whieh is thrown upon

the iodized iodine are so combined, as to be nearly plate--not of the visible image which is rewithout smell. To one part of this solu- ceived and seen on the ground glass, but of tion, add one-hundred parts, or thereabouts, the invisible image formed by the photogeof distilled water, till the liquid has the nic rays. M. Claudet has paid much atcolor of rum, when it will be ready for use, tention to this subject, and kas placed it Having iodized the plate to a rose color, beyond a doubt that the non-coincidence expose it to the vapors of the above liquid. of the luminous and the photogenic focus, till it assumes a violet color, and it will be was the cause of the many failures which ready to be placed in the camera.

take place with cameras of single lenses, Notwithstanding the great degree of sen- the photogenic focus is always more distant sitiveness to light, which the iodized plate than the luminous focus ; but M. Claudet

found, that with some achromatic cameras, * See London and Edinburgh Philosophical' Ma- in which the coincidence should have been gazine, October, 1846, vol xxix., p. 287.

nearly effected, the photogenic focus was nearer the lens than the luminous focus.) in the art of Daguerreotyping has enabled This unlooked for result he ascertained to him to produce portraits of great beauty be owing to an overcorrection of the chro- and force. The portraits taken by Mr. matic aberration of the less refrangible Kilburn, and colored by a chebrated Parays, and he found this “to be generally risian artist, M. Mansion, are exceedingly the case with object-glasses in which, by attractive, while those of Professor Highthe excess of the dispersive power of the school, from America, executed by new proconcave glass, or the irrationality of that cesses, and some of them tinted by peculiar dispersion, the extreme rays of the most methods, exhibit great chemical knowledge, refrangible part of the spectrum are, during and evince much experience in the practice the second refraction, diverged in a greater of his art. He has employed with much proportion than they have been converged success the vapors of cadmium, antimony, by the refraction of the convex lens; and arsenic, and also of several metallic alloys, these rays being nearly invisible, do not and from his devotion to the subject we affect the achromatism of the luminous have no doubt that he will make still rays.” M. Claudet, therefore, recommends greater additions to the resources of photothat the rays of the photogenic spectrum graphy. His very interesting series of pashould be united in one focus, even at the noramic views of the Falls of Niagara, were, sacrifice of the achromatism of the more re- we believe, the first ever taken by the Dafrangible rays. As the photogenic focus, guerreotype. however, will change its place with the co- The Daguerreotype pictures produced by lor and intensity of the light, and with the the methods which we have now described, distance of the object, the photographer being caused by a slight deposit of mershould determine experimentally its posi- cury, resembling the bloom upon a plum, tion in relation to these varying influen- which is effaced by the slightest touch, ces.

could scarcely be regarded as durable or In many of the early Daguerreotypes the permanent works. In order to remedy this pictures were reversed--that is, the right evil, M. Dumas proposed to protect them side of the picture was the left side of the with some transparent vegetable varnish ; landscape ; but this intolerable evil, which but as this coating was not proof against does not take place in the Talbotype, was damp and atmospheric influences, it has soon corrected-in some cases by reflexion never been satisfactorily applied. The from a glass or metallic mirror, and in oth- object, however, which Dumas contemplaters by a prism, which is decidedly the best. ed has been effected by M. Fizeau, by a As much light, however, is lost by these very beautiful and simple process. Having reflexions, and the time of sitting prolong- covered the silver plate containing the piced, artists have scrupled to correct the re- ture with a solution of chloride of gold, version of the picture. M. Claudet, indeed, mixed with a solution of hyposulphite of is, so far as we know, the only person who soda, in certain proportions, and then exmakes a point of correcting the reversion of posing the plate to the gentle heat of a the picture; and he has placed it beyond a spirit-lamp, the metallic gold is precipitatdoubt that a picture not reverted, is a more ed upon the plate, and forms a thin transartistic and truthful representation of the parent coating, which gives a rich tone to individual than a reverted one. We have the picture. The gold precipitated on the long been convinced of this truth; and if plate forms an amalgam with the molecules any person doubts it let him look at the or crystals of mercury, and by adding to two sides of a Calotype made transparent their size increases the brilliancy and force by the process which we have already de- of the picture. Other metals have been scribed, and though the two portraits are precipitated by the electrotype process, but mathematically the same, he will see that the precipitates are less transparent and in the air and even in the likeness, they adhesive. The process of M. Fizeau, beare essentially different.

sides fixing the picture, enables the artist By means of these processes, portraits of to color his portraits-a most desirable rea very superior character are now taken sult, which could not have been otherwise professionally by several distinguished ar-effected. tists in the metropolis, by M. Claudet, Mr. To the same ingenious author, M. FiKilburn and Professor Highschool, each of zeau, we owe the beautiful art of reproducwhom have distinguished excellences of ing the Daguerreotype pictures by the their own. M. Claudet's long experience electrotyp process, which was discovered Vol. XII. No. II.

16

in the same year with the Daguerreotype.* | the battery when put in action. This elegant In this new process metals are precipitated process, however, owing to the breaking of from their solution by the action of electri- the delicate coating which protects the silver, city, the precipitate being deposited on is still susceptible of further improvement. every part of the picture, so that when the M. Fizeau, to whom the photographic metallic film, or plate thus formed, is re- art is so much indebted, has given us anmoved from the surface of the Daguerreo- other method of etching the plate. Heemtype, it resembles it so exactly that it ploys a mixture of nitric acid, nitrous acid, would be impossible to decide which was and chlorohydrid acid, which attacks the the original and which the copy, did we not silver and not the mercury. The chloride know previously of what metals they were of silver is formed by the action of the acid respectively composed. This perfect re- upon the silver, and stops its action, but semblance between the original and its im- the coating of chloride is removed by a sopression shows that the Daguerreotype lution of ammonia, and the biting continuimage consists of minute crystals, produced ed by fresh acid. This operation is repeaton the surface of the plate by the combined ed till the plate is etched. In order to inaction of the mercury and the iodide of crease the depth of the etching, M. Fizeau silver, that the lights arise from these re- gilds the white parts, which he does by fillflexions, and that similar reflecting faces ing the bitten parts of the silver with a are produced on the electrotyped plate. siccative ink. By wiping the surface

As the Daguerreotype pictures cannot be slightly, the ink fills up only the hollow multiplied like the Talbotype ones, it be- parts, and the mercury remains perfectly came desirable to discover some method of unprotected. He then immerses the plate fixing them on the plate by a more perma- in an electrotype battery, charged with a nent tracing than mercurial lines, and to solution of gold, and as soon as the contact make this plate the means of their repro- is established, the gold is precipitated on duction. The first person who partially the white parts only, the greasy ink presucceeded in this attempt was M. Donné, venting the precipitation upon the silver. who, after covering the edges of the plate When the gilding is completed, the ink is with a protecting varnish, poured upon its removed by caustic potash, and the plate surface a weak solution of nitric acid. again submitted to the action of nitric While the pure silver was bitten in by the acid. The etching commenced by the first action of the acid, the other parts, protect-operation is now continued, the part which ed by the mercury, remained untouched, is to remain in relief being protected by provided the action was not long continued. the gilding. A plate thus etched, will give As the impressions given by these etchings a great number of very good impressions ; were very faint, Dr. Berres of Vienna used but as it would soon be worn by the printthe vapor of dilute nitric acid, and applied ing, M. Fizeau recommends, in order to a varnish to the parts of the plate which protect the original, and insure a great required to be protected; but this method, number of copies, that it should be electrorequiring the skill of an artist in laying on typed, so that from one matrix any number the varnish, has been as unsuccessful as of copper-plates may be produced, and that of M. Denné.

from them any number of copies printed for The process of etching Daguerreotypes, publication. though considered, after these failures, as We have already seen that the sun carbeyond the reach of art, has been greatly ries upon his palette only one color. He improved by the agency of electricity paints but with china ink or bistre. From Professor Grove, availing himself of the the pure white of his virgin beam, he reproperty of the Voltaic battery to precipi- fuses to disenchain the mystic hues which it tate at the positive pole metals placed at embosoms and combines. The gay colors the negative pole, places the Daguerreotype of the natural world, whether they sparkle plate at the negative pole, and by the use of in leaf or in flower, on the insect wing or on solutions which attack the pure silver surface the virgin cheek, appeal to him in vain. in preference to the amalgamated metal, Even his own setting glories he refuses to the biting of the silver is effected after it fix. He lights up indeed with new brighthas been immersed only a few seconds in ness the azure vault, as if to entice to the to the Academy of Sciences on the 15th and 25th Cræsus shines dim on his canvas, and he '

refuses to give expression to the scarlet

May, 1841.

vestments of power, and the red banners of will appear to be all but impossible, when

To speak more plainly, the tints of we consider that the photogenic rays which the water-color painter, which correspond form the pictures in the Talbotype and to the solar red, orange, yellow, and green, Daguerreotype, are not rays of light, nor and all their mixtures, appear black upon rays of heat, but are actually invisible radithe Daguerreotype plate, while the blue, ations, with which color has no connexion indigo, and violet colors, are more or less whatever. white. According to M. Claudet, who In the valuable work of Professor Dramade these experiments with his usual accu- per of New York, there are many imporracy, and who has kindly communicated to tant observations, relative both to the theous the result of them, “ Blue appears the ry and practice of photography. We bewhitest, indigo the next, and then violet. lieve that he was the first person who disLight yellow and green appear the darkest, covered what he calls, “ the antagonizing although but little difference can be distin- action of the two halves of the spectrum,' guished between them and red and orange the blue or more refrangible half having a colors.". According to Sir John Herschel, decomposing agency on iodide of silver, and the condensed colors of the spectrum give the red or less refrangible half a protecting the following tints on prepared paper :- agency. He states that there is a certain Red, no tint; orange, a faint brick red; condition of the sky, namely, when it has orange-yellow, a glaring brick red; yellow, such a degree of brightness that the sensired passing into green; yellow-green, a dull tive surface is slightly stained by it, under bottle-green ; green, the same, but bluish ; which the decomposing effect of its light is blue-green, a sombre blue, almost blaek; exactly balanced by the protecting agency blue and violet, black. Hence it is obvious of the other rays—so exactly balanced that that colored paintings and drawings cannot it is immaterial whether the exposure be for be successfully copied by the photographer. one minute or an hour, for the resulting acIf the lights are yellow, they become sha- tion is the same.” An equilibrium in these dows in the photograph, or if the shadows two opposite actions, to a greater or less are blue, they become lights! In order to extent, seems to take place even with the show this curious effect, M. Claudet exhi- solar rays in tropical regions, as if the sun's bited at one of the Marquis of Northamp- light there was intrinsically different from ton's soirées, the head of a female figure, what it is here. “ There are strong reathe hair of which was painted yellow, the sons,” says Dr. Draper, *" to believe it so. eyes red, the lips blue, and the face of vari- The Chevalier Frederichstal, who travelled ous tints of indigo and violet, with the in Central America for the Prussian Goshades yellow. When a copy of this ludi-vernment, found very long exposures in the crous figure was taken in Daguerreotype, the camera needful to procure impressions of picture was perfect with all the effects of a the ruined monuments of the deserted cities correct chalk-drawing. M. Claudet had existing there. This was not due to any another female head executed, in which the defect in his lens. It was a French achrocoloring was apparently correct, but in matic, and I tried it in this city before his which the artist had on purpose employed departure. The proofs which he obtained, yellow, green, and their mixtures to produce and which he did me the favor to show me the lights, and blue, indigo, and violet with on his return, had a very remarkable aspect. their mixtures to produce the shades. More recently in the same country, other The Daguerreotype copy of this picture was competent travellers have experienced like as ridiculous in appearance as the party- difficulties, and as I am informed, failed to colored female head which gave a correct get any impressions whatever. Are these picture. Some enthusiastic photographers difficulties due to the antagonizing action consider it as possible, and even probable, of the negative rays upon the positive ?"* that the gay colors of the natural world In opposition, kowever, to the idea of may yet be brought out by the agency of such an antagonizing action, Dr. Draper light. We have no such expectation ; and himself afterwards affirms, that the red, we consider it to be infinitely improbable orange, and yellow rays which protect the with the sensitive materials now used in plate from the ordinary photogenic action, photography. New materials may doubt were themselves capable, when insulated, less be discovered, which shall receive from of producing a peculiar photogenic effect; the photogenic rays the color of the bodies from which they emanate, but even this *A Treatise, &c. Chap. xii., pp. 197, 198.

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