SCIENCE- G OSSIP. 



213 



CONDUCTED BY 14. FOT7LKES-WINKS, M R.P.S. 



Assistance for Headers. — We are pleased to 

 announce that Mr. B. Foulkes-Winks will commence 

 in the January number a series of instructive 

 papers, which we feel sure will be most valuable to 

 amateur photographers. They will be fully illus- 

 trated, and give useful hints, commencing from 

 the initial stages and progressing to the higher 

 technical work. These articles, being from the pen 

 of a thoroughly practical manipulator, and medal- 

 list in the art, are certain to be of help to both 

 beginners and to the more proficient — [Ed. S.-G.] 



Photographic Questions and Answers.— The 

 Departmental Editor for photography will be glad 

 to answer any questions and to give whatever assist- 

 ance he can to readers. He will also be pleased 

 to receive examples of work from amateurs for 

 criticism, and occasionally will reproduce those of 

 exceptional interest, with remarks from a technical 

 point of view. 



Lantern Slides. — We have lately been experi- 

 menting with various makes of lantern plates, and 

 for rich black tones have found the "Mawson" and 

 Thomas's everything that could be desired. The 

 " Gravura " lantern plates give a very wide range 

 of tones, varying from black to almost a red-chalk 

 tint, according to the amount of exposure given 

 and the quantity of A.C. solution added to the 

 developer. Some very beautiful tones can be 

 obtained on "Alpha" plates by developing and 

 fixing, and, after well washing the plate, immersing 

 it in the following solution until the desired tone 

 is attained :— 



Toning Solution. — Dissolve 1 dram of ammon- 

 sulpho-cyanide in 15 ozs. of water ; when dis- 

 solved add 5 grs. of chloride of gold, previously 

 dissolved in 1 oz. of water. Use distilled or 

 boiled water. After toning, rinse well and stand 

 plate to dry in usual way. It is always advisable 

 to give a final rinse under the tap, and at the same 

 time to gently wipe the film with a tuft of wet 

 cotton wool. It is sometimes desirable to alter 

 black tone lantern slides to a warmer tint. This 

 may be readily done by toning in the uranium 

 toning bath : but before toning great care must be 

 exercised to render the slide free from every trace 

 of hypo. To ensure this it is as well, after 

 thoroughly washing the plate, to immerse it in the 

 following solution for three minutes : — Peroxide of 

 hydrogen (20 vols.), 1 dram ; water, 5 ozs. ; rinse 

 well and proceed to tone 



('milium Toniiiij Solution. — I. Ferrocyanide of 

 potassium, 45 grs. ; water, 10 ozs. II. Uranium 

 nitrate, 15 grs. ; glacial acetic acid, 1 oz. ; water, 

 i) ozs. Mix 1 oz. of No. I. and 2 ozs. of No. II., and 

 immerse plate immediately, keeping the dish well 

 rocked until desired lone is reached. This is for 

 sepia; if a red tone is desired, take twice the 

 quantity of No. I. When the slide is toned, remove 



to a disli of wale] into which a few drops of acetic 

 acid has been added, for two or three minutes. 

 Then wash in running water tor at leasl five 

 minutes, and do not let the water fall directlj on 

 plate. In lantern slides, by whatever process, it is 

 always advisable to make them by reduction, as the 

 results are far more satisfactory than when pro- 

 duced by contact. \ reduction camera is the most 

 com enient method of procedure ; but a very simple 

 and less costly plan is to use one's own camera, 

 be it quarter-, half-, or whole-plate. First procure 

 a 3|in. square carrier for the ordinary dark slide 

 to hold the lantern-plate. Then, by any simple 

 means at hand, fasten the negative to the window- 

 pane, first seeing that the glass is quite clean, and 

 having previously fixed a piece of white paper on 

 a sheet of card or board, at an angle of about 

 45°, outside the window. Focus the negative 

 on to the ground glass of camera, taking special 

 precaution that the front of the camera is parallel 

 with the negative. When the image on the ground 

 glass is in its right position, and perfectly sharp, 

 insert the slide, and make the necessary exposure. 

 It is obvious that one of the chief advantages of 

 this method is that any particular portion of the 

 negative may be reproduced, and this to any 

 desired size, on the lantern plate. Another 

 advantage is that, should the upright lines in the 

 original negative be converged, or out of the 

 straight, they may be corrected and brought parallel 

 by a careful use of the swing back. 



Velox Paper and Developing Cartols. — 

 We have received price list and particulars from 

 Messrs. Griffin & Sons, .Ltd., of 20-26 Sardinia 

 Street, W.C., of their Velox papers and Developing 

 Cartols. After considerable experience with this 

 paper we have found the results satisfactory, 

 especially that obtained on the " Special Portrait " 

 paper. Users of this paper must, however, be 

 warned against the tendency of developing and 

 changing the paper in too strong a white light. We 

 are convinced many of the failures are due to this 

 want of care, and strongly recommend that all 

 manipulations should be carried out in a pale 

 yellow light. It is just as easy to work in, and the 

 results are far more satisfactory. Now that the 

 long winter evenings have arrived, this paper should 

 prove of great value. We have just been making- 

 some trials with the same firm's new P.O. P. 

 paper " Carbona," and we are very pleased with the 

 resulting prints, especially those on the matt paper, 

 toned with chloro-platinite of potassium. This is 

 the toningbath recommended by Messrs. Griffin, but 

 we have found the ordinary ammonsulpho-cyanide 

 and gold toning bath answer perfectly. For a rich 

 red colour all that is necessary is to fix the print 

 in a weak hyposulphite of soda solution, made by 

 dissolving 1 ounce of soda in S ounces of water. 



Photographic Christmas Cards.— We were 



shown a very pretty .-election of Christinas cards 

 the other day at one of the wholesale houses, and 

 these in conjunction with the Carbona paper, form 

 a very pleasing and novel way of sending the Com- 

 pliments of the Season to our friends. In most 

 designs there is a space left on the card, where the 

 photograph is to be slipped in. and if the view has 

 been judiciously selected the whole effeel is very 

 pretty. For making these prints we think there is 

 not anything more suitable than the New- Double- 

 Weight Carbon Velox, a paper that is very thick, 

 and therefore does not require backing or mounting. 



