Imaging unit 5

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Imaging unit 5
2012-11-11 20:31:31
Imaging unit

Unit 5
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  1. photosensitive film is used in what? 
  2. Photosensitive film used in photography responds to what?
    Exposure from photons
  3. Visible light and x-rays are used in what?
    Photosensitive film(used in photography)
  4. What is possible with photosensitive film that's used in photography? 
    It is possible to make film insensitive to portions of the spectrum
  5. how is how is radiographic film constructed? (From the inside out)
    • base
    • adhesive layer
    • emulsion
    • supercoat(overcoat)
  6. What is important about the foundation of radiographic film?
    • Flexible yet durable
    • uniformaly radiolucent
    • film must retain size and shape throughout use and processing
    • thickness ranges from 150-200 micrometers
    • modern base is thin sheets of polyester 
  7. What is the thickness range of radiographic film?
    150-200 micrometers
  8. What was the original base that was used to create radiographic images?
    Glass plates
  9. What were glass plates coated with? Tell about its maintenance.
    • Emulsion
    • maintanance of the glass plates were difficult 
  10. The exposure factors of glass plates were_______________. 
    Very high
  11. What caused the glass plates to be replaced with cellulose nitrate?
    Shortage in glass from WWI
  12. What kind of base was used in the 1920's and 1930's? Why did it not last?
    • Cellulose nitrate
    • highly flammable- led to several devastating hospital fires 
  13. In the 1920's what base was introduced?
    Cellulose triacetate
  14. what was flammable as an equal thickness of paper?
    Cellulose triacetate
  15. What were the disadvantages of cellulose triacetate?
    • Films would warp with age
    • not as resilent as today's polyester films
  16. What is today's base made of and when was it introduced?
    • Polyester
    • 1960's
  17. What are the specializations of film base?
    • Blue tint
    • Crossover
    • halation
  18. Blue tint reduces ___________ and increases __________.
    • reduces eyestrain
    • increases diagnostic accuracy
  19. What is crossover?
    Light from one screen exposed to the opposite emulsion