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: their it recent eculiar escrip- h one is that 3. We is, pro- it from defec- a little ery apt r. To y valu- ashing laze of i water paper, with a c., and iesame All the is with ie best •uld be is very portion ieutral- ved by Itering ) whole. of the metallic ; it to a is most itating h nitric ' silver, allowed to the igether. an am- ieutral. , which urfrom r. The ich is a 1e chief od-cut; i mind been 4 pack i ing. ive dry sed, but ertainly . is ce imself. ssary t0 r smal ys have ntrated ily con- cm in 3 always If the ntity o out and > obtain .. When varnisH answer 5, ifyotl graphil /ription present mences nber to London i, from Thurs- College, solutely a chlo- dly de- ons fo OSTES THE PHOTOGRAPHIC NEWS Vol. VI. No. 215.—October 17, 1862. paper is subjected to the fumes for a short time is sufficient, and too long deposit on _ , nificant in itself, becomes the nucleus of further deposit in the process of intensifying. As we have repeatedly before observed, any deposit on the deepest shadows, becomes equivalent to a given loss of intensity on the dense parts of the negative, inasmuch as it renders so much darker printing necessary to get sufficient depth in the blacks of the print. In reproductions generally, this trouble is felt, and in photolithography must imperatively be avoided, as the method adopted for getting purer whites ; but this often brings another trouble, which renders it only partially successful. It almost invariably happens, especially where a very sensitive collodion and iron development are used, that there is a slight, although sometimes almost imperceptible ’ * 1 the shadows of the negative, which, whilst insig- the same method was mentioned in the letter of our Paris correspondent, who stated, that a French photographer had used it with success. Photographers will be obliged to Mr. Penny for the readiness with which he at once communicated the idea to his bretheren, not the first good idea, by the way, which he has published. Whilst referring to ammonia-nitrate for printing, we may mention that we have been using it recently on albumenized paper, with great success. We made an 80-grain bath and added ammonia until the precipitate was redissolved. We then divided it into two parts, to one of which we added nitric acid until it had a decidedly acid reaction. We then added this to the other: the result was a solution slightly alkaline, consisting of oxide of silver in nitrate of ammonia. The paper is floated from thirty to sixty seconds, not more, and prints and tones very satisfactorily. We had a visit a few days ago from Mr. Carbutt, a photographer in Chicago, U.S., who showed us some very excellent prints, printed, as we were informed, by a very similar method. slightest tint in the whites would be fatal. To surmount this difficulty, Mr. Osborne resorts to the “ clearing up ” process. This consists in flooding the iron developed negative, which at this time does not possess more density than an ordinary collodion positive, with a solution of iodine in iodide of potassium, one grain of the former, to two of the latter in an ounce of water, or more dilute as may be necessary. The slight deposit of silver on the shadows is by this means converted into an iodide of silver, which, on being treated with a very dilute solution of cyanide of potassium, is at once dissolved and removed. After thoroughly washing, the process of intensification may bo THE FUMES OF AMMONIA IN PRINTING. Tm value of a solution of ammonia-nitrate of silver in print- "8 is well known by all photographers of any experience, taper prepared with it is more sensitive, and gives more "gorous prints, and richer, deeper tones than can be obtained ith the plate nitrate solution. Notwithstanding the various Amulae which have recently been given for the use of monia-nitrate with albumenized paper, many photo- Miers find a difficulty in using it satisfactorily. We have just received from Mr. Penny, of Cheltenham, a "egestion for the application of ammonia in a different Panner, which, if a simple method of effecting it can be otnd, will, we think, prove valuable. Mr. Penny says:— "While experimenting upon fuming dry plates with Immonia, it occurred to me to try the effect upon sensitized “bumenized paper. "The result was that it increased the sensitiveness, the "lotr of the print, when taken from the printing frame, was W, and the shadows richer. The paper tones in the Btate bath, quite as readily, and to the ordinary colours; J* if the paper be damp at the time of fuming, it is apt to "ster in the subsequent processes. i "I have not been able to carry out a course of experiments, "the suggestion might possibly be useful to some during “approaching dark days.—Yours truly, G. 8. Penny. “Cheltenham, October 11th, 1862.” REPRODUCTIONS. CLEARING UP NEGATIVES. In the paper on photolithography read by Mr. Osborne before the British Association, there is a hint upon what is termed the “ clearing up ” of negatives, which we conceive to be of great importance, and which, by some of our readers who are not sufficiently interested in photolithography to read the paper carefully, may easily be overlooked. One of the troubles experienced in reproduction, especially of engravings, and other similar subjects, where the presence of pure blacks and whites is of great importance, consists in obtaining sufficient density in the whites, and clearness in the shadows. A slight tint on the whites, is very common in reproductions of engravings. The difficulty arises from various causes, such as the near proximity of the object, the long focus of the lens, the small stop desirable, &c. The use of old collo dion, and long exposure is an uncertain remedy. Intensify ing for the purpose of getting sufficient density, is the usual Afore going further, it is only right to say that this 3, although manifestly original with Mr. Penny, is not Xrely a new one. Very recently, a distinguished Ameri- Bamateur communicated it to us as a most valuable secret, "jh he could put us in possession of, for our own use ; but Bit was given to him, to some extent, under the seal of con- nce, he did not feel at liberty to communicate it for publi- Nion, As the matter is now suggested by an independent Averer, we need not hesitate to add the confirmation Nits value, which our friend’s experience enables us to give. "results were described as possessing a richness and depth irely unattainable by other means, and the printing was ?" to be effected in half the time. The mode of applying r femes of ammonia was as follows:—A little of the strong Btid ammonia is placed in a saucer; for convenience, a A of cotton wool may be saturated with it. This is placed vhe bottom of a box with a well-fitting lid. To the centre .fee lid, inside, is attached a clip to hold the paper. A t of paper is then taken, and two diagonal corners "ght together, and placed in the clip, so that the sheet 1"85 loosely folded, face downwards. The lid is then Afe and the excited paper is subjected to the fumes for a smninutes. A very short time is sufficient, and too long B0sute causes the albumen to be attacked. The operation be performed just before exposing in the pressure Im’ 6 fear that where printing is conducted on a large ^^Professionally, this process will be^considered to involvctoo A? trouble. But with those to whom trouble is a secondary Hi, ’deration, compared to obtaining the best possible results, V,Plan is well worthy of a trial. We were informed by t85ntleman t 0 whom we have referred, in reply to a question 6 Whether ammonia in his dark room, did not interfere V his negative process and cause fogging, that although lotretically he had feared such a result, practically he had MicoUndany kind °f inconv enience. We have an impression, i “ We cannot at this moment verify, that some time ago