The average person thinks of photography in connection with motion pictures, snapshots, and perhaps occasional photographs, but these are only a small part of the total contribution photography makes to the world.

The field of photography as an avocation comes very close home to all of us. No matter what may be our hobby, whether swimming, canoeing, fishing, hiking, or other kindred sports, photography is a natural ally. It is not only the interest that our friends manifest in our pictures that justify their making. It is the pleasure we experience in reviewing the picture record that makes photography so eminently worth while. As time passes and details fade from memory, the pictures of the outings so vividly recall the various scenes and incidents that we live those joyous days over again as often as we wish.

The ever increasing multiplicity of ways in which photography is used commercially makes possible only a bare mention of some of the more important. As a business it consists roughly of four types of work—portrait, commercial, amateur finishing and motion picture work. Through the application of photography there have been many definite advances in observational scientific investigation.⁠[12] Photography is made use of in law courts as evidence in the case of accidents and in deciphering charred records; in dentistry and medicine it enables the doctor through the X-ray to make a definite diagnosis and have records for analysis and study. In meteorological work a study of clouds, storms and floods is made by the aid of the camera, while the astronomer is able through the cumulative character of light action to show stars which are so faint because of their great distance that they are invisible even through the most powerful telescopes. In war times photography is the leading factor in securing much valuable information, airplanes equipped with special cameras being used to locate the enemy’s position, detect camouflage, and make aerial maps from which firing data is worked out. In efficiency tests in the big industrial plants motion picture records are made of the operations both of machines and men to show where excess and loss can be eliminated so as to speed up production. The engineer and the contractor can also check up on the work of individuals as well as make actual records of details and show the progress made from day to day.

And then there is the widespread use of pictures in the magazines and papers both as illustrations and advertisements. There is scarcely an article on the market which is largely advertised that is not accompanied by a cut of some kind. In this connection it must be pointed out the close relationship of photography and photo-engraving. The engraver uses the photographic print to make the cut from which the magazine and newspaper pictures are printed.

Color Photography is another line in which definite advances are being made. Pictures in monochrome while quite faithfully translating color values into shades of black and white and answering all ordinary requirements, yet are most unsatisfactory for depicting the grandeur of a mountain view or the sublime beauty of an evening sunset. Innumerable processes have been brought forward from time to time and many patents have been granted for photographic color processes. However, no method has yet been devised for making pictures in color that even remotely approaches the simplicity of ordinary black and white photography.

The autochrome process as introduced by M. M. Lumière of Lyons, a screen plate process, is perhaps the simplest adaptation. It consists of a glass plate coated with a sticky varnish on which is dusted a mixture of fine starch grains which have been dyed the three primary colors and mixed together in suitable proportions resulting in a colorless coating. Over this is applied a coat of water proof varnish and then a very thin panchromatic emulsion. The exposure is made as in the case of an ordinary plate except that the glass side is toward the lens. By this means the exposure is made through the orange-red, green and blue-violet starch grains which act as filters. The exposed plate is developed for a definite time or by inspection, by the aid of a special green safelight. After rinsing it is immersed in a reducing solution which will dissolve out the finely divided silver forming the negative image. When this deposit has been removed the starch grains transmit light like those which came to them in the camera. The remainder of the silver salts not affected by the primary exposure and development is now reduced to metallic silver. This development must take place while the plate is exposed to a strong white light. The plates when finished must be viewed either as transparencies or on the screen as lantern slides.

Color printing processes are hardly practical for the average amateur. Three negatives are made on panchromatic (color sensitive) plates or films using orange-red, green and blue-violet process filters. Each negative must be printed in its complementary color. The colors in which they are printed may be obtained from pigmented papers such as carbon; or colored inks, paints or other coloring materials may be used. The three carbon tissues or prints are then transferred to the same final support being cemented down in correct register. In spite of all the difficulties attendant on color photography, even motion pictures in colors are now possible.

There have been other advances which are almost unbelievable. Objects more than one hundred miles distant, practically invisible because of the atmospheric haze, have been photographed by suitable color sensitive films and filters. Pictures are made in the dark by means of the invisible ultra-violet ray while there are great possibilities with the infra-red rays and X-rays. With other constant developments in all phases of photographic work, who can prophesy what the future will bring forth?