Suche löschen...
The photographic news
- Bandzählung
- 24.1880
- Erscheinungsdatum
- 1880
- 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-id1780948042-188000001
- PURL
- http://digital.slub-dresden.de/id1780948042-18800000
- OAI-Identifier
- oai:de:slub-dresden:db:id-1780948042-18800000
- Sammlungen
- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
- Bemerkung
- Exemplar unvollständig: Seite 1-82 in der Vorlage nicht vorhanden
- Strukturtyp
- Band
- Parlamentsperiode
- -
- Wahlperiode
- -
- Bandzählung
- No. 1134, May 28, 1880
- Digitalisat
- SLUB Dresden
- Strukturtyp
- Ausgabe
- Parlamentsperiode
- -
- Wahlperiode
- -
-
Zeitschrift
The photographic news
-
Band
Band 24.1880
-
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe 83
- Ausgabe Ausgabe 85
- Ausgabe Ausgabe 97
- 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 445
- Ausgabe Ausgabe 457
- Ausgabe Ausgabe 469
- Ausgabe Ausgabe 481
- Ausgabe Ausgabe 493
- Ausgabe Ausgabe 505
- Ausgabe Ausgabe 517
- Ausgabe Ausgabe 529
- Ausgabe Ausgabe 541
- Ausgabe Ausgabe 553
- Ausgabe Ausgabe 565
- Ausgabe Ausgabe 577
- Ausgabe Ausgabe 589
- Ausgabe Ausgabe 601
- Ausgabe Ausgabe 613
- Ausgabe Ausgabe 625
- Register Index 631
-
Band
Band 24.1880
-
- Titel
- The photographic news
- Autor
- Links
- Downloads
- Einzelseite als Bild herunterladen (JPG)
-
Volltext Seite (XML)
254 THE PHOTOGRAPHIC NEWS. [May 28, 1880. Et ome. THE ORDNANCE SURVEY DEPARTMENT, SOUTHAMPTON. There is always a peculiar charm in visiting a military establishment. Discipline and order manifest themselves in a hundred different ways, and in matters of science prove of the utmost value. This, we should say, is cer tainly the case at the vast photographic and engraving department at Southampton, over which Colonel Cooke, C.B., so ably presides, with Lieut.-Colonel Scott, R.E., as his executive officer. The work here attains a high standard of excellence, and through every detail of a somewhat elaborate process, care and intelligence are at once apparent. The practice of zincography is here seen at its best, and that best is certainly deserving of the highest praise. The buildings at Southampton occupy a space of some thing like seven acres. Here are produced in zincography and in copper-plate engraving those marvels of accuracy, the Ordnance maps, in the production of which an amount of labour and care is bestowed little imagined by the parish officials to whom they are of such service. The Ordnance survey of Great Britain has been going on for many years ; indeed, it is one of those things which may be said to have no end, for though hills cannot sink to plains, nor valleys rise to mountains, yet the boundaries of towns are constantly changing, and the survey of London ten years ago would present a very different appearance from what it does now. Towns of over four thousand in habitants are honoured by a map on a scale of vast magni tude, no less than ten feet, or, to speak correctly, 10'56 feet to a mile, one square foot of map thus representing 500 feet of ground. Ordnance maps of cultivated country are drawn to a scale of 25-344 inches to a mile, or one square foot to 2,500 feet. There is a third series of six inches to a mile, or one foot to 105,600 feet, and a fourth of one inch to a mile ; the latter series being of two kinds, one in which the hills are represented in relief, and the other in which outlines alone are drawn. These four series represent the maps which are the basis of nearly all the maps of Great Britain now published. Specimens of each—Brobdingnagian examples; of zincography and en graving—are shown on the walls of the library of the Southampton establishment, and though they consist of sections of 38 inches by 25 joined together, so perfectly has the work been performed that, save in blank spaces where there is no detail, the joins are imperceptible. Let us suppose that the careful and painstaking Sapper has made his survey, and has executed his drawing. The drawing is sent to Southampton, photographed, and sent to the central office to be examined for corrections ; any alterations—and they are, as a rule, very few—being made on the photograph. When the latter is certified as cor rect, a tracing is made on starched paper in lithographic ink, and then transferred to zinc. This, so far as the large or general scale of ten and a-half feet to a mile is con cerned ; with the reductions a different plan is pursued. By the kindness of Colonel Scott we were enabled to trace the progress of a reduction from its starting point to its completion, and very interesting were the various stages. With experienced Quartermaster McDonald as our cicerone, we first visit the studio. The latter was built by Sir Henry James, and is cruciform in design, its nave and transept, with their circular roof, suggesting a Crystal Palace in miniature. Very pretty to look at is the studio, but not altogether what would be built now-a-days. The management of the blinds requires a little skill, while the studio, being raised some twelve feet above the ground (the lower portion being devoted to printing rooms) instead of on the basement, vigilance is needed to avoid vibration from footsteps. By an ingenious arrangement, which per ¬ mits the drawing to be copied, being shifted easily, so as to obtain a perfectly parallel plane with the lens, a section is suspended ready for copying. “We use direct sunlight when we can get it,” says Quartermaster McDonald, “as we get a short exposure and less reproduction of the ine qualities of the paper.” The camera, a goodly sized in strument, unpolished and homely looking, is mounted on a massive stand, the legs of which slide in a metal tram way. The legs are without wheels, and for an obvious reason. When the true position of the stand has been as certained, there it remains without fear of disturbance until the time when it is necessary to move it. The lens is a doublet well stopped down. While we are in the studio a negative is taken. The ordinary wet process is worked, Hardwich’s collodion being used in preference, owing to I its toughness, a valuable quality in the intensifying method ' adopted. The negative is brought out of the dark room । and placed in a saturated solution of bichloride of mercury until bleached. It is then removed into the open air—a gallery running round the studio enables this to be ! done readily—treated with sulphide of ammonium—which, । by the way, is never allowed to get stale—and well I washed. The result is a negative of a deep brown colour, with clear sparkling shadows capable of producing perfect blacks and whites. So much for the negative. The print is the next step. The sensitizing material is bichromate of potash and gela tine, on unsized bank-post paper—the proportions being bichromate, 3 ounces ; gelatine, 2 ounces; and water, 40 ounces. The exposure is short, apparently about three minutes in diffused daylight, no actinometer being used. When taken from the printing frame the image is visible of a pale, rather dingy, yellow colour. The print is now placed face downward on a plate covered with a greasy ink and passed through a press. Placed in hot water, the latter dissolves all the bichromated gelatine not acted upon by the light, and the superfluous ink is removed by three or four applications of a soft sponge, leaving the image clearly and sharply defined. The next process is the transfer to zinc. We accompany the Quartermaster to another building where the zincogra- graphers are busily at work. Here is a lithographic press, the bed of which is formed of zinc, carefully scraped, and a “ biting ” surface prepared with a fine sand, the grains of which are so small they pass through a sieve of 160 holes to a lineal inch. The plate is damped, and the print, also damped, laid face downward upon it, and passed under the roller. The metal, greedy of oil, and as repellent of water as the back of a duck, receives on its surface a facsimile of the print. The etching solution, consisting of gum-arabic, phosphoric acid, and a solution of nut-galls, is washed over the plate, and bites into those portions not protected by the greasy ink. A little “ dodge ” adopted here is worth noticing, inasmuch as it shows the attention which the workers pay to detail. Directly the etching solution is poured over the plate the zincographer and his assistant begin fanning the zinc vigorously with parchment fans, with the object of hastening the action of the acid, and so being able to use a weaker solution than would otherwise be necessary. An application of turpentine removes all the superfluous ink, and the zincograph is complete. In taking the impressions only one precaution is necessary—the plate must be damped. Were this not done, the ink would flow over the plate instead of being retained only on the zincograph. For the reproduction of drawings and en gravings in lines nothing can be more admirable than the zincograph ; in the reproduction of a tone it totally fails. Prints from a landscape negative were shown us as examples of what the process could do, or, to speak cor rectly, could not do in this direction, and the results were certainly not encouraging. In addition to the zincography carried on at Southamp ton, there is, as we have already mentioned, an extensive establishment for copper-plate engraving. Here copper-
- Aktuelle Seite (TXT)
- METS Datei (XML)
- IIIF Manifest (JSON)