Learn Photography - 35mm Film
By Quinn Sugarlake
Before the digital age when someone wanted to learn photography, they had to master 35mm film. Cameras used film to record images, and post-production happened in a darkroom setting to process the negatives into a permanent state using a chemical process. Once processed, the negative images became "fixed" with the aid of more chemicals. Those fixed negatives were used to print a positive image onto photographic paper.
Prior to 35mm film, images were recorded onto glass negatives, and even before that, they were recorded onto tin. With each advance in technology the art of photography advanced, and became more widely available to the general public.
The basic principle behind film negatives is that light is captured onto the film with the use of microscopic crystals in a compound called silver bromide. They are suspended in a transparent gelatin; this mixture is called emulsion. It is spread onto a strip of plastic - the base. Anyone who wants to learn photography needs to know a little chemistry.
When a solution of silver nitrate is mixed with an alkaline bromide solution in a solution of gelatin, silver bromide is formed. What happens next is called a double decomposition and since the silver bromide is insoluble, it is precipitated.
The emulsion is really a suspension of silver bromide crystals held in the gelatin and becomes the layer of film that is light sensitive. The sensitivity of a film to light is determined by the size of the silver bromide crystals. The larger crystals need less light to produce a well-exposed image than the smaller crystals. That comes with a price, though. Larger crystals make the image appear grainy. Smaller crystals produce a finer image, but require more light to obtain a proper exposure.
If you wanted black and white film that was a fast film, you would get what is called, Tri-X-Pan film. A medium speed black and white film is called, Plus-X-Pan, and slow speed b&w film is called Panatomic-X film. A standard was developed and a number assigned to specific speeds. This number is called the ASA, which stands for, "American Standards Association." If the film has a high ASA number, it will be a fast film. A film rated with a low ASA number will be a slow film. Tri-X-Pan has an ASA of 400; Plus-X-Pan has an ASA of 125 and Panatomic-X film has an ASA of 32.
Once you Learn Photography your images will be taken to a new level. 35mm cameras are available today at great prices! Visit http://www.photographyspy.com for deals on cameras and accessories.
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