The photographic news

• Bandzählung: 12.1868
• Erscheinungsdatum: 1868
• Sprache: Englisch
• Signatur: F 135
• Vorlage: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: SLUB Dresden
• Rechtehinweis: Public Domain Mark 1.0
• URN: urn:nbn:de:bsz:14-db-id1780948042-186800009
• PURL: http://digital.slub-dresden.de/id1780948042-18680000
• OAI: oai:de:slub-dresden:db:id-1780948042-18680000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

THE PHOTOGRAPHIC NEWS. Vol. XII. No. 506.—May 15, 1868. CONTENTS. FAQE A Modification in Transferring Carbon and other Tissues... Mr. McLachlan’s Discovery Collodion Negatives without Glass Iron Development for Gum Plates. By Russell Manners Gordon Pictorial Effect in Photography. By II. P. Robinson Copyright and Piracy On Some of the Changes which take Place in Photographic Materials and Chemicals after a Lengthened Disuse. By John Bockett 229 229 230 230 230 231 233 PAGE Redevelopment by Nitrate of Silver and Citric Acid. By John C. Browne 234 On Blurring, with a New Remedy. By M. Carey Lea 234 Mr. Chance’s Lecture on the Manufacture of Glass 236 Proceedings of Societies—North London Photographic Associa tion—London Photographic Society—Liverpool Amateur Photographic Association 236 Correspondence—Photo-lithography—Modified Honey Process 239 Talk in the Studio 239 To Correspondents 240 A MODIFICATION IN TRANSFERRING CARBON AND OTHER TISSUES. We have recently had our attention called by Mr. William Firling, an ingenious and persevering amateur of Dorchester, to a valuable modification he has made in the mode of transferring the film containing the image in producing photo-enamels, carbon prints, &c., at once eliminating several difficulties, and securing case, simplicity, and certainty in the operation. In M. Joubert’s, or any similar enamel process, in which a film of collodion is used to transport the layer of vitreous colour and organic matter, which form the picture, from the flat glass upon which it was originally produced to the surface upon which it has to be burnt, one of the difficulties consists in getting rid of the collodion before burning. It is often found to resist the solvent action of ether and alcohol, remaining obstinately insoluble. Mr. Filling's method gets rid of all difficulty on this score. In his method of enamelling he prepares a tissue resembling carbon tissue, but containing vitreous colours instead of Indian ink or lampblack. This is exposed under a negative, as in carbon printing, with the prepared side in contact with the negative. After exposure the prepared side is coated with a solution of bees’-wax in turpentine, one ounce of the former in three of the latter. When this is dry it is coated with collodion, and then the tissue is placed in warm water and developed in the same manner as a carbon print. When this is done it is placed upon the enamel tablet, or other surface upon which it is intended to be burnt, to which it is made to adhere by means of gelatine. The elasticity of the collodion allows it to be adapted to convex or concave surfaces without wrinkles, and when it is dry it is only necessary to get rid of the collodion to make the picture ready for firing. The tablet is slightly warmed, which softens the wax between the collodion and the image, and on lifting the edge of the collodion film it can be removed without the slightest trouble, bringing with it the coating of wax, and leaving only the image on the tablet. Mr. Filling adopts a similar plan in carbon printing. After exposing the carbon tissue it is treated with the solution of wax before mounting on the paper with caout chouc for the purpose of developing. The various manipu lations having been completed, and the developed image mounted on its final resting place, instead of sponging the caoutchouc-coated paper with benzole to soften the india- rubber, the mounted print is very slightly warmed, which permits the paper upon which it was developed to be removed at once, taking the wax with it, and leaving the print perfectly clean. Some examples of photo-enamels and of carbon prints transferred to ground glass and to opal glass, which Mr. Firling showed us, illustrated the value of this mode of working, the results being in all cases excellent, and the operation, as Mr. Firling assured us, simple and certain. MR. McLACHLAN’S DISCOVERY. Ma. McLachlan's written and detailed account of his mode of working, brought before the Photographic Society on Tuesday night, does not differ in any material degree from the hasty verbal statement made at the former meeting. After listening carefully to his fullest explanation, we repeat the statement we made a month ago : assuming the facts to be true, and holding him responsible for their truth, the com munication he has made is a most important, as well a most extraordinary one. The facts, however, are not easy to verify, as he now states that for a fair trial of the experiment the silver solution must be exposed to sunlight for three months of the most actinic season of the year. As for the only attempts at verification hitherto made, those of Mr. Spiller, they scarcely support the statement made by Mr. McLachlan, who, however, objects both to the experiments and the account of them. Until we publish the paper in our next it would be obviously unfair to the reader to enter into more detailed comment than we have already made upon his proposed mode of operations. As, however, we give Mr. McLachlan credit for perfect honesty as well as great enthusiasm, wo shall not hesitate to comment with equal honesty upon his statements. The especial end he desires is investigation. Ex perimental investigation will require, he says, three months ; examination of the nature of his claims may be made at once. Mr. McLachlan has a right to expect that this shall be done in a fair and courteous spirit, without the ready jibe—so ready on some lips—and the “mockery which is the fume of little hearts.” Candid and courteous criticism is the compliment fairly earned by the outspoken liberality with which Mr. McLachlan has made his commu nication, and in our next we shall have a few remarks to make on the assumptions on which his paper is based. It is only necessty at present to correct an error in our statement of Mr. McLachlan’s formula a month ago. We then stated that to 1G ounces of a 12 grain iron solution 3} ounces of acetic acid were added ; and this led to the idea in the minds of some that the neutral or alkaline conditions of bath and collodion were corrected by the use of excess of acid in the developer. Mr. McLachlan, in giving his verbal statement of formula at the meeting, said 32 drachms of acetic acid were added ; but in a subsequent conversation, in which we asked him to verify the short-hand notes of his remarks, he gave the formula as 3} ounces, which was incorrect, and, as he now states, must have been a lapsus lingua in the excitement of the moment. As experiment