The Chemistry of Instant Polaroid Film

Introduction

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There is more chemistry in Polaroid’s instant film then you could ever picture. I chose to do instant film because I thought it was a lost gem of the past and wanted to know how instant, instant film could really be. Our lives today are not really affected by instant film.  One because Polaroid is not the company that actually makes the film anymore and a less known company makes the film. Also, there is not a big use for the film since in the modern age everything is digital but it is pretty cool.

Composition of instant film

Silver bromide (AgBr),  hydroquinone(C6H4(OH)2)-decorated dyes cyan, yellow, magenta, dark blue dye or dark room dye, potassium thiosulfate (K2O3S2) ,   developing dye potassium hydroxide (HKO)

Main Chemicals, Compounds, or Components:
Silver bromide (AgBr)

  • A crystalline solid that is light sensitive and captures photons.

  • The bigger the crystal of silver bromide is the more is reacts to different types of light such as green light, red light, and blue light.

  • Specific types of silver bromide are paired up with dyes yellow  with the layer that reacts with the blue light, magenta with the layer that reacts to the green light, cyan dye with the layer that reacts to red light, and then there is a base of black

 

Hydroquinone(C6H4(OH)2)

  • Hydroquinone reduces silver halides to elemental silver. So the picture comes out in colors or just black and white if no specific colors are used.

  • comes after picture is rolled out and so when the developing die goes on the silver and the undeveloped silver halides don't get colored


Potassium thiosulfate (K2O3S2)

  • helps dissolve undeveloped silver bromide so the picture stays and image is created.

  • A developing agent


Potassium hydroxide (KOH)

  • provides alkalinity which helps developing agents to work

  • the most alkalinity compound to use and helps speeds up development so it takes minutes

Chemistry's Role                            

Instant film is all chemistry!  The idea of film is to capture light with certain chemicals light is exposed to the film for a second and a chemical reaction occurs. When the silver bromide is exposed to photons it forms silver atoms which makes a black and white picture.  The most important chemical is silver bromide (AgBr) because it captures the photons. It is a soft, pale-yellow, water insoluble salt. Silver bromide is naturally found as the mineral bromyrite.

    If you want colored film though it is a little more complexed. Colored  film has three layers the top layer is sensitive to blue light the next layer is sensitive to green and the bottom layer is sensitive to red.  Developed color film has a negative image where the colors are the opposite color of the actual scene.  In slide film two dyes attach to the unexposed areas that combine to form the color captured film at the exposed layer.  Instant camera film is just like slide film but the developing chemicals are already in the film itself.  Colored instant film has dyes paired up with  specific types of silver bromide are dyes of yellow with the layer that reacts with the blue light, magenta with the layer that reacts to the green light, cyan dye with the layer that reacts to red light, and then there is a base of black.  When the film comes out of the camera it goes through rollers that goes over a pod that has dark blue dye or dark room dye that gives the effect of a dark room when regular film is developing. The pod also has developing dye that make all the other dyes come out of the negative and come to the top where the picture can be seen.The Impossible Project's film takes 30-40 minutes to develop.


Background Research
In 1947, Eidwin Land invented Polaroid's instant film. The only company in the world that still makes instant film for classic polaroids is the impossible project. The company used old Agfa technology to simulate Polaroid's chemistry and re-establish the production of Polaroid-format instant film. Polaroids chemistry is still a secret and the impossible project had to re-invent the film because polaroid stopped making the film in 2008. It took the company 17 months before they came out with just black and white film.


Resources
How Stuff works

Wikipedia

http://en.wikipedia.org/wiki/Instant_film


Society of American Archivists

http://www2.archivists.org/glossary/terms/d/diffusion-transfer-process


Smash

http://www.smash.com/fascinating-short-film-explores-complex-chemistry-polaroid-instant-film/


The Impossible Project

https://www.the-impossible-project.com/


Chemical and Engineer news

http://cen.acs.org/articles/87/i12/Instant-Film.html


Web elements

http://www.webelements.com/compounds/silver/silver_bromide.html


Development of film explained

  

About the Author
Johnathon Byrd is a junior at Billings Senior high. In his free time he likes to hike, hang out with friends and be creative.  He is also an active member is STEM.
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