Suche löschen...
The photographic news
- Bandzählung
- 27.1883
- Erscheinungsdatum
- 1883
- 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-id1780948042-188300004
- PURL
- http://digital.slub-dresden.de/id1780948042-18830000
- OAI-Identifier
- oai:de:slub-dresden:db:id-1780948042-18830000
- Sammlungen
- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
- Strukturtyp
- Band
- Parlamentsperiode
- -
- Wahlperiode
- -
- Bandzählung
- No. 1291, June 1, 1883
- Digitalisat
- SLUB Dresden
- Strukturtyp
- Ausgabe
- Parlamentsperiode
- -
- Wahlperiode
- -
-
Zeitschrift
The photographic news
-
Band
Band 27.1883
-
- Titelblatt Titelblatt I
- Register Index III
- Ausgabe Ausgabe 1
- Ausgabe Ausgabe 17
- Ausgabe Ausgabe 33
- Ausgabe Ausgabe 49
- Ausgabe Ausgabe 65
- Ausgabe Ausgabe 81
- Ausgabe Ausgabe 97
- Ausgabe Ausgabe 113
- Ausgabe Ausgabe 129
- Ausgabe Ausgabe 145
- Ausgabe Ausgabe 161
- Ausgabe Ausgabe 177
- Ausgabe Ausgabe 193
- Ausgabe Ausgabe 209
- Ausgabe Ausgabe 225
- Ausgabe Ausgabe 241
- Ausgabe Ausgabe 257
- Ausgabe Ausgabe 273
- Ausgabe Ausgabe 289
- Ausgabe Ausgabe 305
- Ausgabe Ausgabe 321
- Ausgabe Ausgabe 337
- Ausgabe Ausgabe 353
- Ausgabe Ausgabe 369
- Ausgabe Ausgabe 385
- Ausgabe Ausgabe 401
- Ausgabe Ausgabe 417
- Ausgabe Ausgabe 433
- Ausgabe Ausgabe 449
- Ausgabe Ausgabe 465
- Ausgabe Ausgabe 481
- Ausgabe Ausgabe 497
- Ausgabe Ausgabe 513
- Ausgabe Ausgabe 529
- Ausgabe Ausgabe 545
- Ausgabe Ausgabe 561
- Ausgabe Ausgabe 577
- Ausgabe Ausgabe 593
- Ausgabe Ausgabe 609
- Ausgabe Ausgabe 625
- Ausgabe Ausgabe 641
- Ausgabe Ausgabe 657
- Ausgabe Ausgabe 673
- Ausgabe Ausgabe 689
- Ausgabe Ausgabe 705
- Ausgabe Ausgabe 721
- Ausgabe Ausgabe 737
- Ausgabe Ausgabe 753
- Ausgabe Ausgabe 769
- Ausgabe Ausgabe 785
- Ausgabe Ausgabe 801
- Ausgabe Ausgabe 817
-
Band
Band 27.1883
-
- Titel
- The photographic news
- Autor
- Links
- Downloads
- Einzelseite als Bild herunterladen (JPG)
-
Volltext Seite (XML)
■Tune 1, 1883.] THE PHOTOGRAPHIC NEWS. 349 7. Discuss the practical and theoretic advantages or disadvan tages of the ordinary printing process over the process known as collod io- chloride. 8. What are the essentials of a good drying box for gelatine plates, or if no box be used, give the conditions most favourable for drying these plates. 9. What is the chemical reaction between the ferrous-oxalate developer and hyposulphite of soda. 10. Describe the method of intensifying a negative with bro mide of copper and silver nitrate, or with a uranium salt, give the formulae you would use, and show the chemical reactions that take place. To what kind of negatives are these intensifiers adapted ? Give the reason for your answer. subs tan spestrum is thrown on paper prepared with the following (i.) Silver bromo-iodide (washed). (ii.) Silver chloride. (iii.) Silver citro-chloride. (iv.) Bichromated gelatine. Give a diagram of the effects of prolonged action of light on each. Make any practical deductions from the results shown. axis as is convenient. Each cord passes forward and backward through four parallel holes in a wooden block, which is attached to the primary axis. The cords can be easily slipped in the holes by pulling their loops, but the friction is so great that they cannot be slipped by pulling at either end. It takes about twice as long to make the adjustment as would be necessary if a more expensive device had been used ; but this device is at once so cheap, so secure, and has so seldom to be used, that it was thought to be the best adapted for the purpose. To prevent rotation from occurring about the primary axis when it is not desired, a bar, parallel to the secondary axis, is attached by its middle point to the primary axis near one end. A cord passes from either end of this bar through cam-shaped clamps, which were originally designed for clamping the cords of curtains with spring fixtures. These clamps are cheap. They are easily and quickly adjusted, and are very secure. The whole apparatus can be located upon the roof of a building, or, if convenient, it can be mounted upon slides, and pushed through an open window when it is to be exposed to the light. If it is to be used upon a roof, a small hut, or shelter of some sort, near by, is a great convenience to the operator, particularly in winter. {To be continued.} APPARATUS FOR PRINTING BY THE BLUE PROCESS. BY CHANNING WHITAKER.* The Mechanism for Adjusting the Surface of the Glass until it shall be perpendicular to the Direction of the Sun's Rays.—1 have found many uses for the blu • copying process in connection with the work of instruction at the Massachusetts Institute of Technology. Notes printed by it are far better and less costly than those printed by papyrograph. I will not detain you now with an account of the uses that I have made of it. I will merely say that more than a year ago I found that my frame, which has a glass 3 feet by 4 feet, was wholly inadequate to the work in hand, and I tried to increase the production from it by diminishing the time of printing. The glass of this frame was horizontal, except when one of its ends was tilted off from the slides which guided it when pushed out of the window ; and I knew that it took three or four times as long to print when the sun was low as it did when the sun was near the meridian. I made plans for mounting this frame upon a single axis, about which it could be turned after it had been pushed through the window, but I saw that no move ment about a single axis would give a satisfactory adjustment for all times of the year, and I considered what arrangement of two axes would permit a rapid and perfect adjustment, at all times, with the least trouble to the operator. It was evident that when the sun was in the equatorial plane, the surface of the glass should contain a line which was parallel to the axis of the earth ; and further, that if such a glass was firmly attached to an axis which was parallel to that of the earth, it would ful fil the desired purpose. For the glass, being once in adjust ment, is only thrown out of position by the rotation of the earth ; and if the glass is rotated sufficiently about its own axis, in a direction opposite to that of the earth, it will retain its ad justment. In order to have the adjustment equally good when thessun Wa8 either north or south of the equatorial plane, it was sufficient to mount a secondary axis upon the primary one and at right angles to it. About this the glass could be turned through an angle of 234°, either way, from the position which it should have when the sun was in the equatorial plane. The Construction of the Adjusting Mechanism.— I desired to have the mechanism as compact and inexpensive as possible, and to have the frame well balanced about the primary axis, in every position. I also desired to have a rotation of nearly 180° about the principal axis. I he plan adopted will be most easily under stood by referring to the drawing which illustrates it. The axes are composed chiefly of wood. They are built up from strips which are 3 inches by 3 inch, and from small pieces of 2 inch plank. They are stiffly braced. A pair of ordinary hinges permit the secondary rotation to occur, while a pair of cast-iron dowel pins, with their sockets, such as are used in foundry flasks, serve as pivots during the primary rotation. The Adjustments.—The adjustment about the secondary axis does not need to be made more frequently than once a week, or once a fortnight. In order to prevent rotation about this axis when in adjustment, two cords lead from points which are beneath the back-board, and as far removed from the secondary • Continued from page 334. PHOTOGRAPHY IN RELATION TO COLOUR. BY 3. R. SAWYER.* In the observations that I venture to place before you this even ing, I am not sanguine enough to imagine that there is much of what is absolutely new to communicate to an audience so thoroughly well up in almost all branches of the photographic art as the members of the parent Society. Whatever of novelty may exist, will arise more from the point of view I take of the subject, and from the practical bearing it has upon the principles and practice of photography. The posi tion of photography is a little difficult to define : it is allied on the one hand to science, on the other to art, without exactly belonging to either. If we analyse its operations, we find that a man can scarcely take a high rank as a photographer unless he possesses a considerable amount of the artistic faculty; whilst it is equally certain that no amount of artistic faculty will compen sate for a lack of knowledge to comprehend, and of power to use, the tools with which the photographer works. But, putting aside for the present the means employed to pro duce photographs, let us concentrate our attention upon what it is that photography undertakes to do for us. Photography will furnish transcripts in mon chrome of works of nature, works of art, and illustrations of the thousand-and-one things and incidents, commonplace or otherwise, that interest us. Were these objects so represented monochromatic, the work of the photographer, both in its artistic and scientific character, would be rendered much less difficult ; but this is eminently not the case. Nature does not employ monochrome; myriads of re flecting surfaces, of different capacities and textures, present to our senses an infinity of colour-gradations changed and modified by play of light and shadow; and it is of as much importance to have the power to re-produce this shifting phantasmagoria as it is to have the power to recognise the artistic capabilities of its com binations. Many valuable papers have been read before you, giving the behaviour of different kinds of sensitive surfaces when subjected to the solar beam as dialysed by the spectroscope; my object, this evening, is to bring before you quite a different set of observations. The practical photographer has to do, as a rule, with surfaces that reflect colour ; and it is important to know in what manner the usual and ordinary colours seen and used by us every day, and observed by us in the colouring of natural objects—I say it is important that the action of those usual and ordinary colours should be clearly understood, and whatever weak points may appear in their reproduction duly noted with a view to discovering that kind of chemical sensitive surface which will give in monochrome the same relations of power, depth, and brilliancy that the colours themselves afford to the optic nerve of the eye. Upon this occasion a comparison of the photographs you hold in your hands with the colour-subject before you will enable you to take stock of the actual position of photography with respect to the reproduction of colour, and quite accidentally it has • Read before the Photographic Society of Great Britain.
- Aktuelle Seite (TXT)
- METS Datei (XML)
- IIIF Manifest (JSON)