Henry Whitworth, Jr,, age 13, of Forest PA  ,

What is Photographic, print paper made from?

A wide awake young photographer can have fun and save money by developing his film and making prints  An experienced expert can make his own film and even hip print paper, though this is a tricky fob and the results are usually far less reliable than bought materials  Film is merely clear plastic coated with chemical,  The paper used to make prints from the film negative is coated with chemical similar to that used on the film  However, the paper is designed to work more slowly than film  • which has to do its work in a split second 

The chemical used to coat film or print paper is called a light  sensitive salt  It is usually one of the silver halides, It is a compound in which silver atoms are combined with atoms of chlorine, bromine or iodine  So long as a light‑sensitive chemical remains in the darks or under a dim red light, the assorted atoms are in small, tightly locked units  When exposed to daylight or white light, chemical changes occur in these individual unite 

A beam of white light starts to break down the small units in the silver compound, The film is now sensitized, or exposed, A bath of developer chemical, such as hydroquinone, will reduce the sensitized units to metallic silver  A fixing bath of hypo will remove the units which did not break apart and set the silver atoms on the film  Running water then washes away all particles except the silver atoms fixed on the film or print 

The faxed silver atoms form the dark and dam patches on the film or print  The light areas are the spots where light did not reach the sensitive chemical and break it apart  This light‑sensitive process can be seen in action with a few special chemicals  The mixing must be done in a dark room under a red lamp  Naturally, one would keep young children away from these chemicals and be very careful when using them 

A solution of silver bromide is sure to demonstrate its light‑sensitive reaction  The basic chemicals are silver nitrate and potassium bromide, A small pinch of chemical is dissolved 3  n its own glass partly filled with water  The two solutions are then mixed to form silver bromide, In the dark room, this liquid is clear, If it is exposed to white light, it turns dark purple  The light breaks apart the small units in the compound and frees the atoms of silver which stain the solution 

Film and print paper control this light‑sensitive process and make it go to work for us  The coating used is an emulsion  It is usually a base of gelatin in which fine grains of some salver halide compound are suspended  The coating is‑applied wet and showed to dry, All this is done under dim, dull red lighting, The paper used for making photographic prints must be firm and satin smooth, The gelatin coating usually adds more gloss to the sensitive surface  when a film is developed, the light patches of the scenery show up dark and the dark patches are light, The negative is placed flat on the print paper, The areas below the light patches of the negative are exposed and turn dark  The areas below the dark patches are protected and stay light