Suche löschen...
The photographic news
- Bandzählung
- 13.1869
- Erscheinungsdatum
- 1869
- Sprache
- Englisch
- Signatur
- F 135
- Vorlage
- Hochschule für Grafik und Buchkunst Leipzig
- Digitalisat
- Hochschule für Grafik und Buchkunst Leipzig
- Digitalisat
- SLUB Dresden
- Lizenz-/Rechtehinweis
- Public Domain Mark 1.0
- URN
- urn:nbn:de:bsz:14-db-id1780948042-186900000
- PURL
- http://digital.slub-dresden.de/id1780948042-18690000
- OAI
- oai:de:slub-dresden:db:id-1780948042-18690000
- Sammlungen
- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
- Bemerkung
- Heft 545 (S. 73-84), Heft 547 (S. 97-108), Heft 589 (S. 599-610) fehlen in der Vorlage. Paginierfehler: Auf Seite 444 folgt Seite 443
- Strukturtyp
- Band
- Parlamentsperiode
- -
- Wahlperiode
- -
- Bandzählung
- No. 560, May 28, 1869
- Digitalisat
- SLUB Dresden
- Strukturtyp
- Ausgabe
- Parlamentsperiode
- -
- Wahlperiode
- -
-
Zeitschrift
The photographic news
-
Band
Band 13.1869
-
- Ausgabe Ausgabe 1
- Ausgabe Ausgabe 13
- Ausgabe Ausgabe 25
- Ausgabe Ausgabe 37
- Ausgabe Ausgabe 49
- Ausgabe Ausgabe 61
- Ausgabe Ausgabe 85
- Ausgabe Ausgabe 109
- Ausgabe Ausgabe 121
- Ausgabe Ausgabe 133
- Ausgabe Ausgabe 145
- Ausgabe Ausgabe 157
- Ausgabe Ausgabe 169
- Ausgabe Ausgabe 181
- Ausgabe Ausgabe 193
- Ausgabe Ausgabe 205
- Ausgabe Ausgabe 217
- Ausgabe Ausgabe 229
- Ausgabe Ausgabe 241
- Ausgabe Ausgabe 253
- Ausgabe Ausgabe 265
- Ausgabe Ausgabe 277
- Ausgabe Ausgabe 289
- Ausgabe Ausgabe 301
- Ausgabe Ausgabe 313
- Ausgabe Ausgabe 325
- Ausgabe Ausgabe 337
- Ausgabe Ausgabe 349
- Ausgabe Ausgabe 361
- Ausgabe Ausgabe 373
- Ausgabe Ausgabe 385
- Ausgabe Ausgabe 397
- Ausgabe Ausgabe 409
- Ausgabe Ausgabe 421
- Ausgabe Ausgabe 433
- Ausgabe Ausgabe 443
- Ausgabe Ausgabe 455
- Ausgabe Ausgabe 467
- Ausgabe Ausgabe 479
- Ausgabe Ausgabe 491
- Ausgabe Ausgabe 503
- Ausgabe Ausgabe 515
- Ausgabe Ausgabe 527
- Ausgabe Ausgabe 539
- Ausgabe Ausgabe 551
- Ausgabe Ausgabe 563
- Ausgabe Ausgabe 575
- Ausgabe Ausgabe 587
- Ausgabe Ausgabe 611
- Ausgabe Ausgabe 623
- Register Index To Volume XIII 629
-
Band
Band 13.1869
-
- Titel
- The photographic news
- Autor
- Links
- Downloads
- Einzelseite als Bild herunterladen (JPG)
-
Volltext Seite (XML)
May 28, 1869.] THE PHOTOGRAPHIC NEWS. 259 I also prepared some plates with a modified coffee process, the only material difference being the substitution of sugar of milk, 20 grains to the ounce, for the loaf sugar usually described. This solution keeps, and can be used for months without exhibiting any symptoms of change. The sugar of milk forms a very hard and dry varnish on the surface of the sensitized film, and another office which it appears to perform is to render the negative soft and harmonious, pre senting violent contrast. That the sugar of milk has this tendency I proved by making some dry plates preserved with sugar of milk alone. Coffee plates prepared by this formula are very sensitive, but not quite as sensitive as thoso by the preceding process. They keep, however, equally well, and, in that respect, as also in quality of the negative, are all that can be reasonably desired ; it is simple and efficient. I have succeeded in perfecting a tea process which is reliable, and in most respects produces results similar to the coffee. I experimented with several examples of Oolong tea, with different results in almost every instance. I then procured some Japanese tea, and the plates resulting from its use were very fine. I have since experimented with different samples, and the results have been uniformly the same. I make a strong tea, using a large table-spoonful, which I put into a bowl and pour on eight or ten ounces of boiling water, then cover it over, and keep it hot for about an hour; then make. I have succeeded in perfecting a tea process which is reliable, and, in most respects, produces results similar to the coffee. I experimented with several samples of Oolong tea, with different results in almost every instance. I then procured some Japanese tea, and the plates resulting from its use were very fine. I have since experimented with different samples, and the results have been uniformly the same. I make a strong tea, using a large tablespoonful, which I put into a bowl, and pour on 8 or 10 ounces of boiling water, then cover it over and keep it hot for about an hour; then make it up to 10 or 12 ounces ; add, while hot, 15 to 20 grains to the ounce of finely pulverized sugar of milk, filter, and, as soon as cool, it is ready for use. I exhibited some plates preserved with this process to the members of the Photographic Society, at one of our meetings last fall, at which Mr. Rockwood was present. He stated that he had used tea for preserving dry plates, and at times produced very fine results; but he had used Oolong tea, and he often found his plates bad where there had been no change except in the tea. If I recollect right, he stated that he published some of his experiments, but, as far as I was concerned, I had no recollection of ever seeing any pub lished process for using tea for a preservative. I have used, in experimenting, loaf-sugar and also rock-candy in these solutions, but prefer, and would recommend, sugar of milk. 1 made a very sensitive plate by adding a grain and a half to the ounce of acetate of morphia to my tea solution; it worked in one-fourth of the time. Whether they will keep I am unable to say. I have one, however, which is several months old, that will test that point when used. There was one drawback, however, to its adoption : the same diffi culty presented itself that appeared in the tannin into which I introduced acetate of morphia; the tea soon became turbid and unfit for use, except, perhaps, as an anodyne. Whether the morphia could not be introduced into these other solu tions, in the same way adopted with the tannin, with the same or still more beneficial results, I have not yet had an opportunity to demonstrate. Since the publication, in the Philadelphia Photographer, of Mr. Carey Lea’s modified Gordon’s gum process, where he claims to have produced dry plates, with his bromide of silver collodion, as sensitive as wet ones, I have applied his gum formula to dry plates.made in the ordinary way ; the only change from Gordon’s is the substitution of 12 grains to the ounce of sugar instead of 5, with the addition of carbolic acid to preserve it. In my experiments last summer with Gordon’s process 1 used 2 drops of the solution of carbolic acid to 5 ounces of the gum solution, to prevent its changing. With this new gum formula I have produced very sensitive plates, requiring from thirty to forty-five seconds’ exposure with an iron developer ; according to my recollection, that was the time I found necessary for the old formula. Those experiments, however, were made in midsummer, which would show increased sensitiveness by the new formula of at least one-third. I have made very beautiful dry plates, about one-quarter more sensitive than the tannin plate, with a strong tea made with white oak bark. I have also used, as a preservative, bisulphate of quinine, Peruvian bark, quassia, rhubarb root, shumao leaves, with varying results. It had become quite a common remark, that it was more difficult to find things which would not preserve dry plates than to find things which would. I have experienced no difficulty of that kind. The effect of Croton water on the sensitive film may be of interest to those New Yorkers who are trying to make dry plates. There are three months in the year in which it can be used without any injurious results, from the first of January to the first of April, and, if the season is cold and backward, to the first of May. As soon, however, as the weather becomes sufficiently warm to cause decomposition of vegetable matter to commence, you will, if you observe closely, notice a change in the sensitiveness of your plate, which cannot be attributed altogether to the change in the season ; and this goes gradually on until something appeas which will strongly remind you of fogging, and yet you will bo hardly able to define it as such, the sensitiveness still increasing as this tendency to fog increases. This went on with my experiments last summer until the middle of June, when the fog became decided, and before the first of July it had become a dirty veil. The negatives produced before the middle of June were good printing negatives, notwith standing the tendency to fog. After this time, until cold weather has prevented decomposition, and the old stock of water on hand has run off and been replaced by that which contains comparatively no organic matter, Croton water is worthless for washing dry plates—for the first or second washing, at least—from May to January. I mentioned to Mr. H. T. Anthony the facts here stated, knowing that he had had much experience with dry plates. He stated that his experience had been similar, and that he attributed the effect observed to animal matter more than to vegetable. He stated that, in the month of June, the Croton water became saturated with fish spawn to such a degree that it clogged the sieves in some places, so that it became necessary to remove it once in twenty-four hours. It would appear from this that a certain quantity of animal or organic matter in the water will give increased sensitive ness to the film, and it becomes a delicate question to deter mine just the kind and quantity to a given amount of pure water, to arrive at the extreme point of sensitiveness with out fogging. All who have ever produced dry plates agree that one of the most important parts of the process is the washings, and that the employment of pure water for the first washing is absolutely necessary. I obtain the water which I use by melting ice ; it can always be depended upon, whereas distilled water, usually obtained at the drug gist’s, frequently contains impurities which render it unfit for washing a sensitized collodion film. I have experimented much with different developers, and have been thoroughly converted to the doctrine of those advocating strong developers. I have always found that a developer at least twice as strong as usually recommended, used with not more than one-half the nitrate of silver com monly used, produces much finer results, besides lessening the time of exposure one-half. Negatives developed with a strong developer and the smallest trace of silver are always soft and full of detail. For a stereoscopic negative 2 drops of a 10-grain solution of nitrate of silver is sufficient. I have succeeded in compounding an iron developer which works well, and the exposure of the plate is reduced about to the same time required when the alkaline developer is used, and the results are as good in every respect; it has the
- Aktuelle Seite (TXT)
- METS Datei (XML)
- IIIF Manifest (JSON)