Изображения страниц


OME attention has recently been given to the subject of photographing shop fronts, and one journal gave an illustration of a method of working which consisted in erecting in front of the shop a large black screen or sheet, and photographing through a small aperture made to admit the lens. The method is thoroughly impractical; the sheet would have to be so large, and would require most elaborate arrangements for supporting it. One authority commenting on the suggestion stated that the focus of the lens to be employed was immaterial. Here again we see a lack of practical acquaintance with the subject; the focus of the lens has a great deal to do with the matter. For the shorter the focus the nearer the camera has to approach the subject, and the nearer it is to the subject, i.c. the shop-front, the wider the range of objectionable reflections. The first point to be observed in this work is to get as far away as the surroundings permit. Further, if the footpath be watered and as much of the roadway as is reflected, one reflection the less will be assured.

If possible, the photographing should be done when the sun is shining on the shop; there will then be less light on the objects inevitably reflected. Undoubtedly the best method of all is to illuminate it at night time by a flashlight, carefully screening the flash so that no surrounding objects receive light. Failing all these much may be done by selecting a judicious standpoint, so as to include as little objectionable reflected representation of a neighbor's goods or signs in the middle of the shop to be depicted. By using a plate several sizes too large and taking the view on one or other side of it much may be done to avoid those annoying reflections. Finally the utmost care should be taken to see the camera front is square to the shop-front.


ACKING PLATES. Exposed and unexposed. The chief plate makers in this country and in Europe have no uniform standard method of packing. their wares; but they have three leading methods: First, they are placed face to face with nothing between the individual plates of the dozen; second, face to face with thick paper grooves or slips at the edges; third, face to face with sheets of thin paper separating the two faces. Now the first named plan deserves the first place: Sheets of glass touching one another-even when their surfaces are not dead plane--and tightly wrapped in paper offer the most efficient safeguard from damage from an accidental blow or fall, and so

[graphic][merged small][merged small]

packed are not liable to any friction from uneven surfaces. The paper slips are an unnecessary trouble and expense, and we have heard of more than one case where one of these slips unperceived in the dull light of the darkroom has been imprisoned in the dark slide and prevented the back from closing light-tight. We have been in darkrooms where they have literally carpeted the floor. The third method is decidedly to be reprehended. There is always the risk of the papers leaving marks of their presence after long storage, and the great danger, when the papers lie quite flat, of the operator picking up a plate and placing it in slide without removing the paper, which often adheres quite firmly and unobserved. There is an adaptation of the first method adopted for their smaller plates by one of the largest manufacturers in the world which is highly objectionable. It consists in packing the plates in pairs, the two plates being formed from one piece cut with the diamond, and broken, but not separated from one another, the film forming a sort of hinge which, of course, prevents any rubbing together during transit. It is, however, a thoroughly mischievous plan in a busy studio. The man in the darkroom has to change his slide with the utmost slickness and rapidity. With the other methods he picks up the plate with one hand, holding the dark slide in the other, and changes without delay; but the "hinged" plates are a two-handed job, both hands being needed to effect the separation. The very great loss of time involved by this can only be appreciated by those who have undergone the worry. In packing plates that have been exposed, and are being carried on a journey awaiting development at home, they should, after being very carefully dusted, be placed face to face with no protection between and tightly wrapped in four or sixes. On no account must they be separated, as we have often seen done, by pieces of newspaper or other printed matter, as this will almost inevitably "set off,” and give a developable image. Great care should be taken to see that no foreign substances is packed up between the plates. We once saw a very remarkable effect produced by this precaution not being taken. By some mischance a small fine stalk of hay had become imprisoned, curled up in almost a circle. When the plates arrived home a piece of glass of circular shape had cracked out of the center of one plate and, of course, ruined the negative.


E HOPE our readers like the new way in which we are printing our cover pictures. The photo engraving is printed on an underlying tint, of a different color from that used in printing the engraving itself, so that the effect of the combination of the two tints is very much richer, and more in harmony with the original subject, than where only one tint of ink is used. We shall change the colors themselves from month to month, to suit the different pictures used for the cover illustration, and to conform with the season in which they are brought out.

Monthly Foreign Digest




At the oceanographic institute of the Prince of Monaco experiments have been made to get photographs of live fishes in natural colors. As the autochrome plates are comparatively slow it was found necessary to first choloform the fish by adding a small quantity of this stupefying liquid to the water in the aquarium. It is not stated whether the fishes suffered any injury from this treatment.-Apollo, No. 318.

* * *


As is well-known the ultra-violet rays act very powerfully on plates and papers. It may be desirable at times to determine if ultra-violet rays are present, especially when printing by artificial light. The following sensitive test paper should be prepared: One part of commercial paraphenylene-diamine is dissolved in six parts of hot water and allowed to crystalize, then 1.0 gm. (15 grains) are dissolved in 14 c.c. (1⁄2 oz.) of water and 4 to 8 c.c. (1 to 2 drams) of dilute nitric acid, made by taking 2 parts of the usual concentrated nitric acid Sp. Gr. 1.2 and 3 parts of water. Suitable paper is painted with the above solution and dried rapidly over a spirit lamp or non-luminous bunsen burner. On placing a strip of the paper in the ultraviolet portion of the spectrum or near a quartz mercury vapor lamp, an open arc lamp, burning magnesium tape the sparks between cadmium points from a powerful induction coil the paper becomes blue in a few minutes. Glass differs very much in its transparency to ultra-violet rays and this paper readily shows just how transparent the glass is.-Apollo, No. 318.



The negative to be printed must be well washed and placed for ten minutes in a one per cent. ferric chloride solution, the gelatine will be tanned in those parts which do not contain developed silver, while the silver in the other parts will be converted into chloride. The plate is then well washed again and dried. When dry the plate should be placed in a mixture of glycerine and water in which the parts not tanned swell and remain moist. In rolling the plate with a glue roller covered with greasy ink the parts which have been tanned will take up the ink. To prevent the breaking of the glass plate when under pressure the negative is placed on a thick rubber plate. After inking, the plate is covered with a sheet of printing paper and several layers of thin blotting paper and the whole placed in an ordinary lettercopying press, and by repeating this, a large number of prints may be made. Care must be taken that the developer used does not harden (or tan) the film of the negative, the most suitable for this purpose is either ferrous oxalate or amidol (diamidophenol).-Photographische Chronik, No. 10.

[blocks in formation]

silk is soaked in it, care must be taken that no lumps are present. The silk must then be dried by stretching it in a suitable frame, meanwhile preparing the sensitizing solution:

31⁄2 ozs.

I dram

Picric acid
Silver nitrate

100 C.C. 4.0 gms. 10.0 gms.

21⁄2 drams The above solution is applied by means of a broad brush and again dried under tension in a frame. The printing should take place under considerable pressure immediately after drying. If the silk is fumed with ammonium hydroxide before printing, the image will be much more brilliant. After printing the silk is washed to remove all soluble silver salts, and then placed in a chalk-gold toning bath and fixed in a four per cent. fixing bath, washed for one hour and stretched in a frame to dry. Then flatten the print by means of a hot sad iron under good pressure. -Photographische Chronik, No. 18, 1910.

[blocks in formation]


20 OZS.

12. C.C.

Water 600 c.c. I oz. Uranium nitrate, 10 per cent 30 c.c. 2 drs., 50 minims Potassium ferricyanide 10 per cent. Ioz. Potassium oxalate, 10 per cent 30 c.c. 11⁄2 drs. Hydrochloric acid, 10 p. c. 6 c.c. Negatives treated with the first solution yielded plates having much coarser grain then when treated with the second solution, the surface also was much rougher. On making a microscopic examination it was seen that a chemical substitution of the silver took place with the second solution. The first solution produced a physical deposit of uranium ferricyanide around the silver grains of the image. Further tests showed that the difference was largely due to the excess of potassium ferricyanide in the first solution. If the amount of potassium ferricyanide is reduced to 12 c.c. (2 drams, 50 minims) the physical deposit of uranium ferricyanide is also reduced. The addition of sulphocyanide salts accelerates the toning due to the precipitation of uranium ferricyanide. For strong intensification the author prefers the old formula without oxalates and containing equal parts of potassium ferricyanide and uranium nitrate, but for toning silver bromide prints the second

formula is better.

-Atelier des Photographen, Vol 14, No. 5. -Photographische Mitteilungen, Vol 44, No. 10.


Glycine, although an excellent developer for plates, has never been suggested for developing bromide paper. A characteristic of Glycine is that it does not cause fog, yielding clear plates; develops slowly, permitting considerable control. The prints have a fine black color. It might also be used with advantage on gaslight papers.



Developer Metric. Water (boiling) 1000 C.C.

33 ozs.

I oz and 5 drs. Potas. carbonate 50.0 gms. I oz., 5 drs. Sodium sulphite 50.0 gms, 21⁄2 drs Glycine 10.0 gms. For use dilute with one to two parts of water and add bromide solution if necessary.-Apollo, Vol. 14, No. 319.

« ПредыдущаяПродолжить »