55* 



RECREATION 



the plate or paper covered during the first 

 exposure, and then successively uncovering 

 the additional parts until all is exposed. 



We tried this series of experiments but once. 

 That solved for us the problem of exposure in 

 negative-making. The negatives then obtained 

 were the charts by which we determined our 

 latitude. Knowing the results obtained by a 

 given exposure, with a certain quality of light 

 and a specified stop, we calculated our exposures, 

 not for the minimum nor the maximum length 

 in which there could be obtained a good 

 negative, but about midway between these 

 factors, and it was seldom that we went wrong. 



If the beginner will learn, by experiment, his 

 latitude he can more easily determine an ex- 

 posure which will give a good negative. He 

 will soon acquire confidence and eventually be 

 making his exposures by intuition, and making 

 them right. 



lenses of the same focus working at the same 

 aperture. 



Focal difference is the difference in the 

 length of the chemical and optical focus. 



Blue Tones on Platinum 



Very pleasing moonlight effects may be ob- 

 tained with platinum paper by using the 

 following formula for the developer: 



Oxalate solution (i :$) i ounce 



Ferricyanide of potassium (10 per cent. 



solution) 3 drams 



Glycerine 2 ounces 



Water 4 " 



Print rather deeply, and use the brush 

 method of development. When developed, the 

 prints have a greenish tone, which quickly 

 changes to a pretty blue in the acid bath. The 

 said bath to be one-half the strength usually 

 employed for platinotype, and prints to be left 

 in it only long enough to clear the whites. 

 With prints made from contrasty negatives one 

 gets a two-color print, the deeper shadows 

 developing black and the lighter portions of the 

 print coming out a blue similar to that of "blue- 

 print" paper. 



Facts About Lenses 



In speaking of camera lenses, focus is the 

 point at which the rays of light intersect which 

 fall upon the lens parallel to its axis. 



Back Focus. — This is the distance between 

 the back lens and the ground-glass or the 

 sensitive film when in focus. 



Focal Length, Focus or Equivalent Focus. — 

 The focus of parallel rays entering the lens. 



Focal length is the distance from the lens at 

 which the rays of light unite, which fall upon 

 the lens parallel to its axis. The focal length 

 is dependent upon the curvature and combina- 

 tion of the lenses. 



Depth of focus in a lens is the same for all 



Dark-Rooni Hints 



A little citric acid in the water for rinsing 

 velox prints is a good preventive of stains. 

 It is especially useful in hot weather. 



Alcohol flowed over a plate will stop frilling 

 immediately. But never use alcohol on a film 

 negative, for alcohol will attack the celluloid 

 support and ruin the negative. 



If you use the pyro developer and, after fix- 

 ing, the negative is of a yellow color, the yellow- 

 ness can be removed by immersing the negative 

 in a saturated solution of alum to which has 

 been added a small quantity of citric acid 

 solution, the amount of the latter not being 

 material. But if the negative is very thin and 

 weak, it will be of a better printing quality if 

 the color is not removed. 



Our Position 



To be of equal service to the beginner with 

 a little 2 x i\ camera and the advanced worker 

 who uses a box of mahogany with morocco 

 bellows and fitted with a modern anastigmat; 

 to make no discrimination between the technical 

 and the pictorial worker, and to encourage all 

 to advance and be more progressive, is the pur- 

 pose of this department. 



We hope to stimulate activity in outdoor 

 work with topics which shall be a help to the 

 worker in summer, fall, winter and spring. 

 We expect to have something practical to say 

 about rainy-day work, enlarging, lantern slides, 

 sensitizing papers, supplementary lenses, color- 

 ing prints and lantern slides and the prepara- 

 tion of colors. If our readers do not see what 

 they want, let them ask. The Camera Depart- 

 ment is for them, and they are invited to use it. 



In the expression of opinion we shall be 

 governed by our convictions, without catering 

 to any class or being controlled by popular fads. 

 To those who differ with us, we concede that 

 in their opinions they are honest, and the gulf 

 between is not too wide to be bridged. We will 

 not straddle the gulf, but goon record advocating 

 a higher order of technical work. Although 

 believing that definition and detail belong to 

 the pictorial as well as to the other branches, 

 we have no quarrel with those who are not of 

 our way of thinking. We seek no proselytes. 

 We court opposition. We will not be silent; 

 and if we displease, we will stand as a target 

 to be shot at. 



