Of all the fields of applied science, there is perhaps no other that has such a universal appeal as photography. While a science in the true sense of the word it enters so intimately and frequently into contact with our daily lives that we hardly realize its scientific aspect.
Photography is simply the making of permanent images of natural objects on suitably prepared surfaces by physical and chemical means. The process is easily understood and the actual making of good pictures is simplicity itself. The light reflected from the subject being photographed passes through the lens and forms an image on the sensitive material at the back of the camera. An exposure of only a small fraction of a second, if the light is good, affects this material but not to the extent of forming a visible image. The actual image is brought out later by a chemical process called “development.” After being “fixed” so the image won’t fade, the “negative,” as the film or plate is now called, is washed and dried and is then ready for printing. This is done by allowing a given amount of light to pass through the negative onto a piece of sensitive paper with which it is placed in contact. After being developed, washed and dried, this paper is the finished print or picture.
Photography had its early beginning back in the fore part of the 18th century[1] when the “Camera Obscura” was devised.
This was a box equipped with a lens at one end and a piece of ground glass at the other, used by artists to trace a picture on the glass. Some time later various experiments were made to find something to replace the ground glass which would permanently retain the image. Eventually it was discovered that silver chloride would darken upon exposure to light and that hypo would remove the unexposed chemical, thus fixing the image more or less permanently.
Later came the daguerreotype and the wet plate process. The latter was very cumbersome, but many beautiful pictures were made by it, as witnessed by Brady’s collection of Civil War pictures. These were succeeded by dry plates which in turn have quite largely given way to films.
Photography as it exists today covers a very broad field, and many books have been written on the subject as a whole and its various phases. In compiling the material for this Little Blue Book, an attempt has been made to include only those topics which will be of interest and assistance to the average amateur photographer. Scientific processes are explained in such a way that the beginner, with no previous experience in the making of pictures, should be able to understand the various steps as they are taken up, and to get good pictures. The last chapter is devoted to the scope of photography, its practical applications, and to some of the developments that are now taking place.