Suche löschen...
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
- Lizenz-/Rechtehinweis
- Public Domain Mark 1.0
- URN
- urn:nbn:de:bsz:14-db-id1780948042-186200003
- PURL
- http://digital.slub-dresden.de/id1780948042-18620000
- OAI-Identifier
- oai:de:slub-dresden:db:id-1780948042-18620000
- Sammlungen
- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
- Bemerkung
- Seite 1-72 fehlen in der Vorlage. Vorlagebedingter Textverlust.
- Strukturtyp
- Band
- Parlamentsperiode
- -
- Wahlperiode
- -
- Bandzählung
- No. 181, February 21, 1862
- Digitalisat
- SLUB Dresden
- Strukturtyp
- Ausgabe
- Parlamentsperiode
- -
- Wahlperiode
- -
-
Zeitschrift
The photographic news
-
Band
Band 6.1862
-
- Ausgabe Ausgabe 73
- 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
- Register Index 619
-
Band
Band 6.1862
-
- Titel
- The photographic news
- Autor
- Links
- Downloads
- Einzelseite als Bild herunterladen (JPG)
-
Volltext Seite (XML)
Fei [Feb. 21, 1862. THE PHOTOGRAPHIC NEWS. 94 pon u5 develop and which matter is used as a ret toay be i myself w spectfu Broad 1 Sm—, produce stains and patches in this latter process. I have often heard operators remark that a stain visible only b) reflected light was of no importance. I cannot subscribe to this opinion ; whatever may be the cause of this stain, 11 differs in colour from the surrounding parts, and if saf darker, being composed of the same matter as the light parts Marior floatin 1 set Dinan, 1 am r rnealin. natc of bated prepar ing to you tc I am, i Dina [The PS.—] One figui exposed i [We ci ment are We know Toom, I, this dark stain may obstruct in a greater degree the reduc tion of the surface beneath, or if the stain be lighter, m” admit an unequal reduction in the opposite direction ; let time obi those who use redeveloped negatives make careful obserge ' can r tions on their printing qualities, and 1 think we shall the’ second ] learn the origin of mealiness in toning. I have a strong quired 1 notion that all gold toning processes arc perfectly analogoui My con’ and with your permission 1 may another time endeavour !0 Would b show that the gold of the old hypo toning bath acts just •* s6conds • the same manner on the proof as it does on the alkaline bath 8eco1 and that the difference is more apparent than real. I fookapi! and repl the amount of chloride, irregular toning takes place, and the gold bath is exhausted without aiding the operation. I What I have attempted to describe will also explain, I think, why washing the proof in water containing chloride is conducive to the production of mealiness, and also thal water containing organic matter may check the action o> toning. I have already trespassed so far on your patience that I will avoid adding more, otherwise I could mention many known facts in support of the view I have here give# of this part of the process.—Yours respectfully, E. E. L. P.S.—There is one other matter in connection with mealiness in toning worth observing. I allude to the fact that this defect is not inherent in the process of alkalis toning, else it would have occurred when this process first became so common. If, therefore, the cause be unequal, reduction of the silver of the proof, whence arises this u equal reduction? It is, I believe, admitted, that son’ negatives produce this more than others. Now, my sugget tion is, that iron development has brought this upon u The majority of iron developed plates require redevelop ment. I think everyone has felt how very easy it is to produced by combination of gold and organic matter, and the toning takes place more equally. 1 don’t know if I have explained my ideas on the subject so that you can un derstand my meaning, but if I am not quite right in my view I think I have indicated the direction in which the dif ficulty lies. I think it will also be found that my sugges tion explains most of the phenomena attending the efforts to overcome this very serious difficulty.—I am sir, yours respectfully, E. E. L. The same correspondent writes further as follows :— I endeavoured in my last note to explain that I understood this defect to arise from a rapid and unequal liberation of chlorine, caused by the action of the silver of the proof in contact with the gold of the toning bath, for it should, I think, be kept in mind that the metals still retain and can be again reduced to their metallic form. What I wish particularly to correct in my former note is the notion that I there gave that I thought free chlorine unnecessary and injurious in the process of toning. This is not my idea, as I believe it to be the real active agent in the process, and that toning takes place in proportion to the amount of free chlorine present, and also the greater or less rapidity with which it is liberated ; it will, therefore, be understood that it could only be objectionable when existing unequally on the surface of the paper, and producing un equal reduction of the gold. That chlorine is essentially an agent in toning may, I think, be shown in many known facts, as, for instance, the great difficulty in toning proofs that have been previously fixed. There are, however, some retarding agencies also to be taken into consideration besides the absence, more or less, of chlorine. The most active of these retarding agencies will, I think, be found in organic substances. Judging by my own experience, every organic salt of silver, when pre sent in any quantity, exerts some retarding influence, and to this cause also may, perhaps, be traced the beneficial influence of the acetate of soda, checking the too rapid liberation of chlorine, and allowing more equal distribution of the precipitated gold. The reason why mealiness does not occur on plain paper proofs, I take to be owing to the absence of organic matter on the surface, as it is well known that the silver salts are more rapidly reduced on this kind of paper, and therefore, when under the influence of the gold bath, the amount of reduced silver being large in proportion to free chloride present, we do not see those rapid and extreme changes of tint so common with albumen paper. In the sei d'or process also, it was formerly recommended to add hydrochloric acid to the bath, and this, however injurious to the permanency, certainly aided rapid toning. 1 would also call attention to the different action of the newly prepared gold bath, and the same bath when left some time before using. This I take to be owing to the fact, that some of the chlorine being liberated from the gold to form chloride of sodium by the decomposition of soda, effects this new combination very slowly, and it is during this time, and whilst the chlorine is in a nascent state, that it acts most energetically in reducing the gold. It will, therefore, be seen, that according to my view, chloride is essential; but that being exceedingly energetic, it rapidly frees itself in the presence of the new action taking place between the two metals, and if there be not a large amount of reduced silver present, the act of substitu tion soon ceases, and the gold is deposited, not on the proof, but m the dish, and the hypo afterwards removing the un reduced silver, the slight amount of reduction becomes visible in the pale grey colour of the part not effectually acted on. In conclusion, my view is, that as free nitrate is necessary to aid reduction of the chloride of silver, so also some free chloride is necessary to aid in the reduction of the gold of the toning bath; but that the gold is deposited on the reduced silver in proportion to the amount of reduction, and that where the amount of reduction is not in excess of Sib,—I have of late read much in the PIoTOGnart to wait News on the subject of mealiness intoning. Although "yselfw always tone by the alkaline chloride of gold process a# 1 Pay. I 1 use albumenized paper I have never met with the abo" ther the annoyance. For the benefit of others less fortunate, if y produce think it worth while to give insertion in your Journal W Content, these remarks, I will detail the process I employ. It w Space in communicated to me, in its main features, in the course Fespectfu last summer by Mr. Bashford, a professional photograpb at Jersey, to whom, therefore, as far as the process itself’ concerned, 1 surrender whatever merit it may possess. I print a little, but not much, beyond the intensity wish the finished picture to retain. On removal from " pressure-frame the proof is washed in two or three wal®. for several hours. When I have the choice, I give pre ence to soft water for this part of the process, but do P2 find that hard water exerts any injurious action. My ton' 11 ' bath is prepared as follows :—I take of chloride of gold 0 grain dissolved in six ounces of water, and this is rende" me to t ' alkaline by four drachms of a solution of phosphate of s07 suggest; of the strength of ten grains to the ounce of water. This0 can spea sufficient to tone at least eight pictures of the size of 2! tiveness; inches by seven. In cold weather it expedites the operat" the pictu to raise the temperature to something like blood heat. ,J in the s The proofs are retained in the toning bath until . j proc shadows by transmitted light appear of a dark chocolthe gelat brown; they arc then washed in several changes of Wa success of and fixed in a hypo bath of the strength of six ounces usual acic the pint of water, in which they remain from fifteenofor as aci twenty minutes, undergoing but little change by tr4jall event mitted light, though by reflected light the cold violet always es gives place to a warm dark brown. I should add that * tone, an a10 lcuuUh U-- 1′8*- FO‘I1 ’ Warding agent, it follows th#' has beer at any r Jeers. Sm,- rity on made a tained i trait cal in a pc picture, deal in 1 the “ sp in getti taken m
- Aktuelle Seite (TXT)
- METS Datei (XML)
- IIIF Manifest (JSON)