The photographic news

• Bandzählung: 6.1862
• Erscheinungsdatum: 1862
• Sprache: Englisch
• Signatur: F 135
• Vorlage: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: SLUB Dresden
• Rechtehinweis: Public Domain Mark 1.0
• URN: urn:nbn:de:bsz:14-db-id1780948042-186200003
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• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
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• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

246 THE PHOTOGRAPHIC NEWS. [May 23,1862. the paper from a cord, which is placed in an inclined direc tion over a board, or anything that will carry a cup to receive the drippings; the remaining moisture may be drawn off by a piece of bibulous paper. In this manner I saved from fifteen sheets of paper one and a-half ounce of solution, containing eighty grains of nitrate of silver. The next point is the recovery from the washing of the prints before toning. This operation of freeing the prints from nitrate of silver is not so easily accomplished as might be expected. It adheres to the paper very strongly, and the bulk of it can only be removed by at least three changes of water. The prints should soak in the first water for fifteen minutes, and be afterwards moved about: the operation is greatly expedited if hot water be at hand. Prints washed in this manner gave for the fifteen sheets of paper a solution which yielded 350 grains of chloride of silver. I now come to the hyposulphite fixing bath, which is thrown away more frequently than the water used for wash ing prints. This, for the fifteen sheets of paper upon which landscapes had been printed, yielded 180 grains of metallic silver. The methods adopted for precipitating silver from the washings and fixing baths arc to be found in all books on photography. I may, however, mention that it will be found desirable to keep two stock jars—one for the washings, and one for the fixing baths. From the former of these chloride of silver may be precipitated by the addition of common salt; but such a proceeding cannot be adopted in the latter, as chloride of silver is soluble in hyposulphite of soda. Another course must, therefore, bo adopted, and the most simple is to add sulphide of potassium, and thus precipitate the silver as a sulphuret. My reason for recommending the use of two jars is, that when chloride of silver can be precipitated, it is of a known value; the sulphuret, however, arising from the use of sulphide of potassium is a variable compound, and the quantity of silver it contains can only be ascertained by trial. Sulphide of potassium has, however, a very disagree able odour, and the operation should, therefore, be conducted out of doors. There are other methods which do not involve this inconvenience, and for which I refer to Hardwich’s Photographic Chemistry, &c.; but the plan I have mentioned is the most simple, as the precipitation may be done in the old way, and may be continuous. If an excess of chloride in the one case, and' sulphide in the other, be kept in the jars, the operation goes on, and it is easily ascertained whether they be exhausted, by removing a small portion of the clear liquid, and testing it with a fresh solution of chloride or sulphide. As the latter sub stance, however, is sometimes slow to act in the case of weak solutions, a small quantity of sulphuretted hydrogen gas may be used; but a better method is one which I have adopted at the suggestion of Mr. Caro, an ingenious chemist in the establishment of Messrs. Roberts and Dale. It is simply this : —Take a test tube, and partly fill it with some of the clear solution ; in this place a small quantity of caustic soda, so as to make the solution caustic, drop in a fragment of grape sugar, and heat the whole over a spirit lamp or gas-burner: if there be a trace of silver present, it is immediately preci pitated in the metallic state* This method is indeed the best that can be adopted for dealing with the bulk of the solution, if the trouble of heating it be not regarded. So far the savings treated of have reference to the printing process; but there are other sources of loss to the photo grapher. For instance, it is a common practice to wash out vessels which have contained nitrate of silver at the sink. I find that a dish for floating a whole sheet of paper, and which is 24 inches by 20, retains upon its surface a quantity of solution, at sixty grains to the ounce, which after close draining yields 25 grains of chloride of silver ; and when we consider how often this operation of washing dishes, measures, bottles, and other utensils takes place, it will be seen that a great loss is sustained. Again : it is a very common practice to throw away fife 1 papers. I find that such a piece as this, and which is eight inches in diameter, retains 15 grains of nitrate of silver, the solution used being 60 grains to the ounce. In preparing dry plates, which have to be washed after leaving the silver bath, there is much to be saved. In washing a series which gave a combined area on one side of 480 inches, and which were sensitized in a 30-grainbati, the washings afforded 35 grains of chloride of silver. There is also a continual waste by spilling solutions, and these may be recovered simply by keeping blotting-paper ai hand to absorb the fluid. In developing collodio-albumen plates, a large quantity of silver is often required to get up the intensity, and a ven' small quantity of this goes to the picture; as it is renewel when it becomes dirty a great sacrifice is made. This refuse may be added to the stock jar containing the hyp® baths. • PHOTOGRAPHY IN THE TROPICS. BY war. FITZGIBBON.* Fort some months past I have been promising myself towrite you, but the multiplicity of my engagements, and my busi ness occupations, added to no small share of laziness, have prevented me ; at last, however, I have made an effort, an 1 ! I give you its result. First, I enclose you a few stereoscopic views, and shall occasionally send others, provided you like them. By the first friend I find going home I shall forward some nega tives for your Photographic Society; of course I do a® 1 know whether you are forming a collection of views, fro® different parts of the world, but if not, I would suggest ili and I am pretty sure if other brethren of the photograph 11 ' art feel as I do, they will not refuse a little labour to add their mite to the collection. I have read so much about processes, toning and fixing &c., by this method and by that, during the last five yeafs that I have become thoroughly bewildered ; you will pro bably laugh when I tell you that I have scarcely ever see a toning or fixing process published that I have not tried: some would work, others failed, as to the results stated, in my hands, and others were worthless; as I never made but a’few ounces of each, the loss could not be great, and every thing was worth a trial. Instead of throwing them away, I put them all together in a glass jar, holding about thre f gallons, and to these I added occasionally an old hypo batl ! Imagine to yourself what a toning and fixing bath it is, 8 mixture of nearly everything used by anyone ; and, as to proportions, well, the less said about that the better. Afe" weeks ago it came into my head to try the mess, and tl stereoscopic views numbers one, two, and three are the • suit. The albumen paper I prepared myself, fifteen graiol of chloride of ammonia to the ounce of albumen, floated fo ■ three minutes, the albumen four days old before using, anl Saxe paper: silver bath, eighty grains to the ounce, a® 1 one drop saturated solution of citric acid to three ouncesi floated for five minutes. This I have worked for the las’ twelve months, and always with excellent results. I ove print a little, and instead of washing in water I wash in • solution of chloride of sodium, two ounces, to eighty ouno of water; in this the print changes rapidly, first bronzing and finally to a dirty red or brick colour ; I now wash several waters until the saline taste is removed, and the” pass to the mixture above, and leave it until I get the to® I like, say from twenty to forty minutes, afterwards "oTa as usual. Now, whether these prints will fade or not 18 0 question; so far I have been very fortunate, and it rar happens that any of my proofs fade. I may here reman that some two years and a-half ago, I toned some albuns prints as follows, and out of over one hundred not one “ faded, and I work it now in preference to any other, exceP * Mr. Slabley illustrated this experiment. * From the American Journal of Photography-