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
- 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. 1159, November 19, 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)
November 19, 1880.] The duration of exposure will, of course, depend upon the nature of the light employed, as well as the illuminating power of the lens and the number of diameters the object is magnified. After exposure the slide is closed and carried to the dark room, when the plate is developed. We will suppose that a satisfactory negative has been taken, and dried, the next step is printing a positive for the lantern. The proceedings will be a counterpart of what takes place in making a transparency for enlargement. A warm colour may be imparted to the transparency, when dried, by plunging it into a solution of mercuric bi-chloride (again see instruc tions for intensifying negatives) for one or two seconds, and afterwards into the hyposulphite fixing bath. The transparency may now be thoroughly washed, dried, and fitted up for the lantern. Stereoscopic photographs of objects of relief may be obtained by moving the lamp about a foot, while the blended instruments remain stationary. Two negatives are taken : in one the lamp throws the shadows to the right, in the other negative to the left. When combined in the stereoscope the object appears in perfect relief. ON A ME I HOD OF IMPROVING PRINTS. A valued correspondent has enclosed for our criticism duplicate specimens of prints, from different negatives, one of the duplicates being an ordinary print, and the other an “ improved ” print. A careful comparison leads us to say that the “ improvement ” is one of real and not merely of theoretical value. The method adopted is the simplest possible, and can be executed by anyone. It consists in sunning the back of the print after the picture has been sufficiently printed. Let us describe the two prints from a portrait negative we have before us now. The ordinary print shows that the negative is rather hard in character, the delicate tones in the highest lights being only partially and certainly insufficiently visible ; the portrait, in fact, looks as if it had been printed from a negative produced by the old pyrogallic acid and silver development. The improved print, however, is vastly different. The patches of white are no longer apparent, the detail in the high lights are brought up, and there is a mellowness about the picture which could never have been produced from a nega tive which furnished the first print we examined, unless there was some “ dodging” about it. When we examine the back of the print we find that it is of a grey black colour; in fact, of the same depth of tint that is produced when plain salted paper is fully exposed to light. W hen the print is examined by transmitted light, it appears perfectly opaque, showing that the action of light has penetrated deeply into the surface from the back. At first it was a matter of surprise that with such a deep printing the albumenized surface of the print had not been markedly dis coloured in the whites as well. But a little reflection showed that this would not be the case, since the blackening would commence at the back surface, and only feeble light would penetrate to the albumenized sur face after the first impact of light. We were informed that the back of this print had been exposed for one hour to bright sunlight. Placing the two prints side by side, the contrast was very marked. The half tints had all been proportionately darkened. Thus, for instance, the back ground in the original print, which was of a very pale grey tint, a tint which might be called a mixture of three-quarter white and a quarter black, had become considerably darker, being equal to a mixture of about half white and half black' The highest points of light remained apparently of a nearly pure white, while, as before said, the. shades in the high lights of the face and hands were materially darkened. The deep shadows appeared to be entirely unaltered. There are two ways which suggested themselves of accounting forthis effect. Some foreign albumenized paper is remarkably thin and transparent; and if prints be mounted on coloured or tinted cards, the colour or tint is invariably seen through the albumenized surface ; and we have noticed that where India tint mounts were used there was an apparent strengthen ing of the shades in the high lights. When a print is sunned at the baek, we in reality diminish the thickness of the white substratum on which the picture rests, and the blackening might probably show through the picture, and produce the same effect as if thin albumenized paper were mounted on a dark mount. We made a practical experiment in the matter, and found that this would not wholly account for the result. The other way by which we might account for it is that there is a slight blackening of the albumenized surface by the light penetrating through the paper. We believe that this, combined with the practi cal thinning of the white substratum, is the true cause of the excellent results obtained. It has been suggested to us that the same results are acquired by slightly tinting the albumenized surface before exposure behind the nega tive, similarly, in fact, to that described by Mr. Blanchard in our last “Topic of the Day.” This undoubtedly does improve a print from a hard negative, but it is always easy to detect the artifice that has been employed, the picture always looking dead, and over the higher lights there is frequently a change in tone which often degrades the subject. If our theory be right, that the result obtained by sunning at the back is partially due to diminishing the thickness of the white substratum, it is evident that sunning the albumenized surface can never give results equal to those obtained by sunning tie back. We have before us examples of landscape subjects treated in the same manner, and certainly there is a harmony of gradation introduced in the “ improved ” prints which is altogether absent in the others. We cannot help thinking that after a few trials, when prints have to be made from hard negatives, sunning the back of prints will be found to be an excellent and legitimate way of improving what would be otherwise faulty—perhaps “ lampblack and whitewash.’’ Slotrs. We publish a paper to-day of more than ordinary importance. We mean Professor Hartley’s “ Application of Photography to Chemical Research ”; photography has done yeoman’s service in many branches of scientific research already, and its usefulness in the domain of chemistry is very clearly set forth by Professor Hartley. The Photographers’ Benevolent Association should bo doing well. We paid an evening visit to the Pall Mall Exhibition last week, and were agreeably surprised at the numerous company assembled. We are glad to see that heads of firms (as well as assistants) are beginning to recognise the aims of the Association ; and since none of us know how soon bad times may overtake us, to assure ourselves against them, if we can, ought to be our first object. With the new year we earnestly hope that a large addition may be made to the roll of the Association. A varnish or cement, which goes by the name of Chinese varnish, and renders cardboard or thick paper as hard and horny as papier maehe, is easily prepared from blood, lime, and alum. Three parts of fresh blood, well beaten up to prevent the formation of fibre, is mixed with four parts of slaked lime, and a little alum, the thick-flowing mix ture that results being at once ready for application to paper or card.
- Aktuelle Seite (TXT)
- METS Datei (XML)
- IIIF Manifest (JSON)