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Silver and Photography
by Brittany Schultze
Physical Geology
Fall 2017Spring 2017

Silver and Photography

    Silver is a metal with an atomic number of 47, its density is 10.501 grams per cubic centimeter, and silver is useful for various things.  Silver and silver compounds go back to about 5,000 years of use.  Pure silver is the best conductor for electricity, heat, and a pure reflector for visible light.  The use of silver and sterling silver for coins, mirrors, batteries, silverware, and jewelry have shaped the world.  The power of silver compounds is immense and have even progressed the world of photography.  Both silver bromide and silver nitrate have made the struggle of a photograph back in the mid-1800s available.  Silver really improved an image to appear and stay visible for long periods of time and has even made the most vivid images yet.

    Silver bromide (AgBr) is a soft yellow compound which is a water insoluble salt.  Silver bromide is particularly known for its relative sensitivity to light.  The struggle of a lasting photo ranged from the 1800s well through the 1900s.  Once silver bromide was discovered to be light sensitive this became a key component is upcoming photographic materials.  Bromine is created at the surface of a crystal.  Light sensitivity of the compound allows silver halide crystals be used in a gelatin to be applied as an emulsion on the surface of  film, tin, or paper to create an image.  The process of the halide crystals formed by precipitation producing small uniformed crystals called grains.  When exposed to light the chemical reaction changes and exposes a picture seen by the naked eye.

    Silver bromide was important for getting rid of silver iodide which was previously used before silver bromide was suggested.  During the 1870s factories were using the gelatin that was used to apply the emulsion on dry plates.  These plates were way more sensitive than the precious plates they used which were coated with collodion.  The act of changing the plates speed up the production and helped with the evolution of hand held cameras rather than needing a tripod as a stabilizer.  Silver bromide is endothermic requiring the necessary energy produced by light.


Image result for silver bromide on film

    Silver nitrate (AgNO3) is also light sensitive and is used in the film and paper for photography.  Germicidal activity takes place with the silvers salt to create a reaction with light.  Silver Nitrate is an inorganic chemical that has antiseptic activity which is usually colorless or white.  It has a crystalline structure which turns from its colorless or white state to black when exposed to organic material such as light.  The chemical activity of silver and sunlight makes a vivid and detailed image appear on its specific support.  Natural silver darkens when exposed to light.  It was sought that chemistry could be the answer to solve this issue from the shadows in silver.  The debate between heat and light was the cause of this and in 1720 a German physicist named Johann Heinrich Schulze had determined the culprit.  He experimented by baking silver nitrate in an oven and it was revealed that the light rather heat caused the shadows or discoloration in the silver.

    Johann Heinrich Schulze had experimented with the silver nitrate to write messages on glass jars by putting stencils on the glass.  The jars were filled with chalk and silver nitrate.  After discovering that silver nitrate could possibly write a message it took decades before anyone took this process into creating an actual photograph.  The chemistry was there, yet no one seemed to use the light sensitive chemicals just yet to create an actual image.


Image result for silver nitrate on a plate for photography


    Through years of trial and error as the knowledge began to grow in the 18th century the understanding of the process came to fruition.  During the 1770s a co-discoverer of oxygen named Carl Wilhelm Scheele examined silver and its properties.  He discovered that there was a reduction of the metallic silver when the silver is exposed to sunlight.  Not only did he discover the lack of metallic silver but found the problem in fixing the image from the camera-obscura.  He experimented and tested that ammonia stabilizes silver from darkening.  Solving the shadows in silver with the ammonia would save the images on silver from tarnishing and being hard to see.

    Photo sensitivity is a major role in photography. There are many components that take place when trying to create a photo.  Such as the shutter of the camera-obscura, the ISO which is where the light sensitivity takes place, and the f-stop or aperture that determines the amount of light through the lens.  Since the mid 1800s photography has been expanded.  Around 1938 the publication of paper was discovered due to the large amount of research with chemistry and physics with silver halides.  This discovery was the change the photographic industry needed.  Photons occurred on the grain create electrons which chemically react with the silver metal thus a negative is created.  There can be a larger concentration of the silver atoms ranging from 5 to 50 silver atoms when more photons are hitting a particular gain.

    A English physicist, Thomas Westwood and a chemist Humphry Davy both experimented and found their own discoveries with silver and its benefits with the art of photography.  Westwood used trial and error putting ideas together until he found something that worked in the 1790s.  Davy did the same and published his own findings along with Westwoods in 1802.  The image was considered a fail when they tried because the result of the photo was to faint and didn’t properly react with the silver nitrate enough to create detail. They decided to take a different approach and cover a white surface with silver nitrate and place it being a painting on glass to successfully get in the right direction.

    The production of prints began in the 1816 when a Frenchman named Joseph Niepce and by 1820 he was able to reproduce a print.  He was using a process called heliography or sun writing.  This major come through was the evolution for the production of prints that all began with the experimenting of silver and its light sensitivity to light.  This shows how silver has only evolved the art of photography.  Creating an image that can last a lifetime and where it all began.  If it wasn’t for silver and its compounds the production of modern day photography wouldn’t be as advantaged as it is today.  Both silver bromine and silver nitrate have affected to film and its sensitivity to light, and the process of a everlasting photo.  Therefore, silver is safe to say it was a main component in where we are today with the photographic world.  A picture is a documentation of history and because of silver we can see what once was.

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