Amateur photography. 



131 



So zealously guarded. I am aware that 

 many advise against the use of an acid fix- 

 ing bath, and probably will continue to do 

 so. My own experience is absolutely in its 

 favor, and I have constantly employed it in 

 the form following for the last 14 or 15 

 years. For lantern slide work I particu- 

 larly recommend its employment. Fading, 

 marks of any and every description, have at 

 various times been attributed to its employ- 

 ment, but I have never had either a negative 

 or a lantern slide fade, and I seen no rea- 

 son for an acid fixing bath to cause fading 

 if property made. 



Prepare the bath by dissolving in 10 

 ounces of water one ounce of sodium bisul- 

 phite; in another 10 ounces of* water, 4 

 ©unces of sodium hyposulphite ; then, while 

 stirring, pour the bisulphite solution slowly 

 into the soda solution. When mixed, the 

 formula will stand thus : 



Sodium hyposulphite 4 ounces 



Sodium bisulphite 1 ounce 



Water 20 ounces 



On removing the slide from the fixing 

 bath and examining it before a piece of opal 

 or ground glass, it should appear crisp, 

 without any appearance of inkiness in the 

 shadows, and when laid on a sheet of white 

 paper the extreme high lights should have 

 the appearance of being bare glass. 



For warm black, try the following amidol 

 developer : 



Amidol 20 grains 



Sodium sulphite 240 " 



Ammonium carbonate •. 20 " 



Potassium bromide 20 " 



Water 10 ounces 



The exposure for warm black colors, 

 when using the foregoing, will be about 

 double the exposure required for black, and 

 development will be rather slower; it 

 should not be carried so far, however. 



When the production of warm colors is 

 attempted with gelatine plates, it is better 

 to adopt pyrogallol as the developer. Not 

 that warm colors can not be obtained with 

 the modern reducing agents, but pyro and 

 ammonia undoubtedly produce them with 

 greater facility than the others do. The 

 subjoined formula has given me good 

 browns with about 5 times the exposure 

 needful for black. With some plates, to 

 produce brown colors, it may be necessary 

 to add more bromide : 



A. Pyrogallol 30 grains 



Sodium sulphite 120 " 



Citric acid 3 " 



Water 10 ounces 



B. Ammonium Bromide 40 grains 



Liquor Ammonia (880) ....30 minims 

 Water 10 ounces 



Take equal parts of each to develop. 



When developing for warm colors, the 

 image acts differently from a black im- 

 age. With the latter the gradations appear 

 crisply defined on the surface of the film, 

 but with warm colored images the picture 

 seems buried in the film, and is only seen 

 when examining the plate by transmitted 

 light. This appearance is puzzling to the 

 novice, and misleads him into giving greater 

 density to the plate than is desirable. Only 

 experience can enable him to judge when 

 correct opacity has been reached, but he will 

 find, where warm colors are in question, 

 that a small apparent density will prove on 

 fixing to have been ample. 



The development of lantern plates in the 

 production of warm colors is often a te- 

 dious operation, requiring perhaps 10 or 15 

 minutes, and there seems no way of curtail- 

 ing and retaining at the same time the qual- 

 ity of the image. Loss of time may be pre- 

 vented by using a grooved tank and leaving 

 the plates to develop while other exposures 

 are being made. Development is so slow 

 that over development need never be feared. 

 The temperature of the developer should 

 never be, below 65 degrees F. 



Should warmer colors than those given 

 by the foregoing developer be required, they 

 may be obtained by adding to each ounce 

 of the mixed developer 20 or 30 minims of 

 a 10 per cent solution of ammonium carbo- 

 nate. It has been stated, but not on suffi- 

 ciently good authority, that the use of car- 

 bonate causes fading. In place of adding 

 the carbonate as a 10 per cent solution, it 

 may be combined with the developer in 

 bulk, in which case the following pyrogallol 

 formula is a convenient one : 



A. Pyrogallol 20 grains 



Ammonium bromide 20 " 



Sodium sulphite 120 " 



Sulphite acid 25 minims 



Water 10 ounces 



B. Liquor ammonia (.880) . . . .100 minims 



Ammonium carbonate 20 grains 



Water 10 ounces 



Take equal parts of each to develop. 



When toning lantern slides there is al- 

 ways some danger of the gelatine becoming 

 stained by the toning agent ; in which case 

 the high lights, which should be absolutely 

 transparent gelatine, have their original 

 purity degraded by the ground color of the 

 slide. This fault is especially noticeable 

 when toning slide* with the uranium and 

 ferricyanide toning bath. Unless great care 

 has been exercised a brown tint pervades 

 the whole of the slide where clear gelatine 

 should exist, due to the toning agent hav- 

 ing stained the gelatine at the same time 

 that it toned the image. 



Many, if not all, toning processes have, 

 at the same time, a slight intensifying ac- 

 tion, and this intensification makes itself un- 



