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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. Talbot'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.”
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 salt.
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
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 waring 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.t 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
the calotype process could be simplified. This yellow tint from the negative picture, Mr. with sixty grains of crystallized nitrate of silver
gentleman directs that the paper be washed over 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 polassium 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 by the same authority, to be prepared by using a
fit for 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 iodide of potasincrease its transparency. Mr. Talbot sium, and five grains 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 compose the oxide of silver, and form a colorless
(though neither of them separately), are able to deof nitrate of silver, before it is put into the iodide 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 has 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 sali (3 or 4 oz. to
in Photographic publication he makes good negative 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 nepending on a combination of iodine, silver, I gative copies as usual.
upon these proportions. A much weaker solu- Mr. Talbot himself, which have been chiefly tion of the nitrate may be used, and this, on the taken from works of art, public buildings, score of economy, is important. The most satis, and landscape scenes, and the portraits exfactory preparations which I have yet employed ecuted in Scotland, by Messrs. Adamson per first with a solution of silyer, as above, and and Hill, and several private individuals, then with a solution of twenty grains of the and in London by Mr. Collen, have not bromide of potassium in one ounce of water; and, been surpassed, and we believe scarcely as I have before stated, the formobenzoate of equalled, by those of any other persons ammonia and silver, formed by washing the paper who have employed processes different from first with the formobenzoate, in the proportion of that of Mr. Talbot. fifteen grains of the salt to one ounce of water,
In referring for a and then with the nitrate of silver, as above. In proof of this to the different numbers of good sunshine an edifice may be beautifully copied the Pencil of Nature, published by Mr. by either of the two last processes in a minute, Talbot, in which the plates are pressed by and by the others in about two minutes. To the agency of light alone, without any
aid preserve these pictures of a clear white, it is ad- whatever from the artist's pencil, we canvisable that they should be soaked in water for a not withhold our admiration of the genius minute, previously to the application of the gallic and patience with which he has overcome acid. “Dr. Ryan has shown the necessity of some
difficulties which many of his friends care in the use of the iodide of potassium, into a thought to be unsurmountable in the prosolution of which Mr. Talbot recommends the duction of such a work. The large vonitrated paper to be placed for a few minutes. If lumes of Talbotypes published by Messrs. the paper is left too long in such a solution, the Adamson and Hill, at the price of £40 or iodide of silver will be dissolved, that salt being £50 each, and now in the possession of one soluble in an excess of iodide of potassium. or two of the most distinguished artists in Simply passing the paper through the solution London, evince also the perfection of Mr. appears to answer every purpose effectually. Mr. Collen has modified Mr. Talbot's process, by
while the beautiful Talbrushing over the paper with a weak solution of botype miniatures of Mr. Henry Collen, the ammonio-nitraie of silver, and in using the touched up and improved by that eminent same solution in combination with the gallic acid, artist, show how much is yet to be accominstead of the nitrate of silver. It does not, how. plished by the application of artistic skill ever, appear to me that any advantage is gained to the original productions of the solar by this mode of proceeding. A careful adjustment of the best proportions of the ingredients re
pencil. commended by Mr. Fox Talbot, will be found to
Having thus given our readers some acafford better results in a shorter time." —Research- count of the Talbotype, and of the art of es, &c., pp. 66-68.
taking sun pictures upon paper, an inven
tion wholly English, and wholly due to the Instead of dipping the sensitive paper in genius of Mr. Talbot, we shall now prodistilled water, after it has been washed ceed to give a similar account of the Dawith the strong solution, No. 1, Dr. Ad-guerreotype, an invention wholly French, amson of St. Andrews has avoided this by and the most important improvements upon weakening that solution with four times its which we owe to French artists and French bulk of distilled water, and taking off the philosophers. superfluous moisture by blotting paper.
In the year 1814, M. Nicephorus Niepce Such is a brief account of the various of Chalons sur Saone, had directed his atprocesses which have been regarded as im- tention to Heliography, as he called it, or provements on the Talbotype. We cannot, to the subject of fixing the pictures in the from our own experience, venture to say camera-obscura by the agency of light. that they are all inferior to the original He had discovered the remarkable property process of Mr. Talbot, or that they contain which light possesses of either solidifying, no important additions to the chemical or of diminishing the solubility of certain agents which he employs, or to the methods resinous substances, according to the duraof manipulation which he used; but we can tion or intensity of its action, and he was positively affirm, without the fear of contra- thus led to the following heliographic prodiction, that the fine pictures produced by cess :
Mr. W. Furlong prepared his iodized paper by
"I fill a wine-glass hall full with pulverized assimply washing his paper in a solution of iodide of phaltum. I pour upon it, drop by drop, the essen. silrer, in strong solution of iodide of potassium, and tial oil of lavender, till the bitumen can absorb no thus produced very fine Talbotypes.
more. I afterwards add as much more of the es.
sential oil as will cause the whole to stand about|of petroleum instead of washing it with the three lines above the mixture, which is then oil of lavender and petroleum solvent. covered and submitted to a gentle heat, until the The substitution of a film of iodine for a essential oil is fully impregnated with the coloring matter of the bitumen. If this varnish is not
varnish, which failed in the hands of of the required consistency, it is to be allowed to Niepcé, became the foundation of Daevaporate slowly, without heat, in a shallow dish, guerre's success, and having once obtained care being taken to protect it from moisture, by a material so sensitive to the action of which it is injured, and at last decomposed. A light, the French, artist overcame all the tablet of plated silver is to be highly polished, on other difficulties with which he had been which a thin coating of the varnish is to be ap- surrounded. plied cold, with a light roll of very soft skin; this will impart 10 it a fine vermillion color, and cover
While occupied with these interesting it with a very thin and equal coating. The plate researches, M. Niepcé died in 1833, and is then placed upon heated iron, which is wrap- on the 14th June, 1837, his
M. Joseph ped round with several folds of paper, from which, Isidore Niepcé, entered into a new agreeby this means, all moisture bas been previously ment with M. Daguerre, that they should expelled. When the varnish has ceased to sim carry on their heliographic inquiries for mer, the plate is withdrawn from the heat, and their mutual benefit, and that the process left to cool and dry in a gentle temperature, and should bear the name of Daguerre as its protected from a damp atmosphere.
sole inventor. “The plate thus prepared may be immediately
M. Niepcé pursued his submitted to the action of the luminous fluid, in
father's process without making any essenthe focus of the camera. But even after having tial improvement upon it, while Daguerre been thus exposed a length of time sufficient for brought his own to such perfection that the receiving the impressions of external objects, no-old process was entirely abandoned. The thing is apparent to show that these impressions discovery of Daguerre was announced in exist
. The forms of the future picture remain 1839, and the extreme beauty of the picstill invisible. The next operation, then, is to dis
tures he exhibited at once surprised and engage the shrouded imagery, and this is accomplished by a solvent.”
delighted the scientific world. M. Arago,
whose great discoveries on light entitled This solvent consists of a mixture of one intrusted with Daguerre's secret, and with
him to the confidence of the inventor, was part by volume of the essential oil of laven- that devotion to science, and to the inteder, and ten of oil of white petroleum.. A rests of its cultivators, which we desire to vessel being procured of a sufficient size, see more frequent among philosophers, he enough of this solvent to cover the plate is resolved that while France had the honor poured into it.
of so great a discovery, it should also have
the higher glory of rewarding and honoring « Into this liquid the tablet is plunged, and the the discoverer, and of making it a present operator, observing it by reflected light, begins to to the whole civilized world. With these
erceive the images of the objects to which it had objects in view he persuaded the French been exposed gradually uniolding their forms, Government to give Daguerre an annual though still veiled by the supernatant fluid, con. tinually becoming darker from saturation with pension of 6000 francs (£500), and varnish. The plate is then lifted out, and held in Niepcó a pension of 4000 francs (£334).* a vertical position till as much as possible of the The bill received the unanimous assent of solvent has been allowed to drop away.” both Chambers, and was signed by the
King on the 15th June, 1839. The silver plate is now carefully washed,
While science continues to interest and by being placed upon an inclined plane, over confer benefits on our species, the noble which a stream of water is made to run, in liberality of the French Government will order to clear away the remaining solvent never be forgotten; but though a grateful that may adhere to the varnish. In this posterity may feel and express its gratiprocess the light has solidified the varnish, tude, it will launch its fiercest invectives and the parts upon which the shadows felí against the laws and legislature of England, being more soluble, will be more acted upon for having wrested from its subjects the by the solvent. On the recommendation of Daguerre, Niepcé substituted Iodine for
* Daguerre himself proposed a reward of 8000 his varnish, and Daguerre improved the francs, to be equally divided between him and process by using the resin of the essential Niepcé. The Government assented; but on the oil of lavender, dissolved in alcohol, and ground of Daguerre's having agreed also to publish
his secret of Dioramic painting, his pension was by exposing the silver plate to the vapor raised to 6000 francs.
high privilege purchased for them by The specification declared it to be indis-