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105 Cards in this Set
- Front
- Back
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Digital Imaging
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electronic signals captured by sensors & displayed on computer monitor
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Radiograph
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image produced on photo sensitive film by exposing it to radiation and processing it
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Image Receptor
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sensor or phosphor storage plate
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According to FDA what must be used on sensors for infection control
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clear disposable, fluid-impervious barriers
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TRUE or FALSE:
Digital image receptors "are" able to tolerate heat sterilization |
FALSE: they CAN NOT tolerate heat sterilization
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2 basic methods to get digital x ray image
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direct imaging & indirect imaging
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in Direct imaging
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solid-state sensor is the image receptor
(contains xray sensitive silicon chip w electrical circuit embedded in silicon) |
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CCD (charge-coupled device) most commonly used receptor
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also used with telescopes, fax, personal data assistants, video cameras, and panoramic machines, plus other extra oral imaging
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Indirect Imaging
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Phosphor Storage Plate (PSP)
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Phosphor Storage Plate Imaging Systems
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*image receptor thin & flexible
*size of reg film *coated with phosphor crystals *phosphor layer stores photon energy for some time *scanner reads info on plate w laser beam releasing energy converting to digital image |
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TRUE/ FALSE:
latent image remains on PSP before scanning for minutes to hours depending on environment it is in |
TRUE: latent image remains minutes to hours
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TRUE/FALSE:
if PSP exposed to bright light and warmth this "will not" release energy before read by scanner |
FALSE: exposure to light or warmth WIL release energy
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After PSP is scanned, they are exposed to bright light that
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ERASES all remaining energy....plate is ready to be used again
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Digitized
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scanning of traditional film based radiographs into a digital image
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Digital Imaging Electronic Image Enhancement and change
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*Contrast *Brightness *Image Size (zoom) *Sharpness *Inversion (white to black--black to white) *Pseudocolor alteration
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Positioning Instruments (dental film & sensor holders)
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hold and position dental X-ray films or digital sensor in pt mouth
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Keeps pt hand & fingers from exposure to radiation
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positioning instruments
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Sensor holder vs Xray holders primary difference
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size & shape of holder
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Advantages of Digital Imaging
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*immediate viewing
*less radiation *no chemicals *enhancing *no more lost films *communication w other dentists |
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Disadvantages of Digital Imaging
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*cost
*Converting previous xray to digital *learning computer software *thick rigid sensors *infection control |
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Bean Alignment Device
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assist in positioning PID in relation to tooth and film or sensor
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PID
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position indicator device
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Intraoral Film
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film that goes in patient mouth
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Emulsion
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coating on film containing energy sensitive crystals
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Emulsion composed of
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*silver bromide
*silver halide *silver iodide |
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layers of film
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*film base--clear cellulose acetate
*thin adhesive attaches emulsion *gelatin suspends emulsion silver crystals over base *silver halide crystals absorb radiation *protective layer--thin transparent coating protecting emulsion |
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Latent Image
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image produced on film when radiation interacts with silver halide crystals, but not visible until processed
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Film Speed
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amount of radiation required to produce radiograph of standard density (darkness)
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Film Speed Determined by
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*Size of Silver Halide Crystals
*Thickness of emulsion *Presence of special radiosensitive dyes |
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TRUE/FALSE:
Flim speed determines how much exposure time is required to produce image on film |
TRUE: fast film require less radiation
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Larger the Silver Halide Crystals
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Faster the film speed
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Film Speed A through F classified by
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ANSI--American National Standards Institute
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Only film speeds used in Intraoral Dental Radiography
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D....E....& F speed films
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Types of x-ray film
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*intraoral--inside mouth
*extraoral--outside mouth *duplicating |
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Intraoral Film
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emulsion on both sides of the film....requires less radiation to produce an image
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Film Packet
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film is seal to protect from light moisture
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Intra oral film packets
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available in boxes of 25, 100 or 150 films (one film packet and 2film packets)
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Packet Information Labelled with
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*type of film
*film speed *number of films /packet *total #of films in box *film expiry date |
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Black Paper Film Wrapper
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protective sheet that covers film & shields from light
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Herringbone Pattern seen on film
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when film packet is positioned backward in mouth
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Lead Foil
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Hazardous waste not disposed of in regular trash
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Tube Side
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solid white side of film packet faces the teeth and tubehead
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Label Side
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side of film packet with an opening flap, faces toward tongue when taking X-ray
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5 Basic Film Size
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*child yngr than 3--#0
*narrow anterior--#1 anterior adult & kids *adult size ---#2 *preformed bitewing--#3 *occlusal--#4 |
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Extra oral Film (outside mouth)
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examine large area of head and jaws
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Common Extraoral Films
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*panoramic & cephalometric
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Panoramic
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wide view of upper & lower jaws
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Cephalometric
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shows bony soft tissue of facial profile
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Extra oral films supplies in
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*boxes of 50 or 100 films
*5x7 & 8x10 |
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Extraoral films boxes are labelled
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*type of film
*film size *# of films inside box *film expiry date |
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Film Cassette
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*plastic or metal case used to hold film & protect it from exposure to light
*holds film in tight contact w intensifying screen *ridgid & flexible styles |
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True/False:
Exrtaoral film have no raised dot, --front of cassette marked with L & R |
True, L distinguishes Left side, R distinguishes Right side
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True/False:
Front side of cassette made of plastic,permits passage of xray beam, back side made of metal, reducing scatter radiation |
True:Front side of cassette always faces patent during exposure
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Intensifying Screen
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intensifies or increases effect of radiation decreasing amount of exposure time needed (like D,E &F in intramural films)
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Phosphor
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coating on intensifying screen that gives off light when hit by radiation
(same material that coats phosphor plates in intraoral digital imaging system) |
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True/False:
Sandwiched btwn intensifying screens, the cassette containing film is affected by light from phosphor & x-radiation |
True
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Speed of Crystals
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larger the crystals--faster the screen--poorer the definition
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Type of screen uses a common type of phosphor
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Calcim Tungstate---produces blue light
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Rare Earth Elements (another type of phosphor)
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produces green light
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True/False:
Rare earth element screens 4x more efficient converting xray energy into light than calcium tungstate.... |
True: therefore are faster requiring less exposure time
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2 Types of film used in Extraoral Radiography
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screened film & non screened film
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Screened film
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sensitive to light emitted from intensifying screen
(more sensetive to light emitted by phosphor than radiation) |
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True/False:
Use of screen type film & intensifying screens REDUCES amount of radiation to patient |
True: patient radiation reduces
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2 types of screens used in Extraoral Radiography
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*Green-sensitive-used with rare earth screens
*Blue-sensitive-used with calcium tungstate screens |
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Nonscreen Film--no screen required
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*exposed directly to X-rays
*emulsion is sensitive to xray exposure instead of fluorescent light *requires more exposure time, NOT recommended for dental radiography |
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Duplicating film
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only used in darkroom and is NEVER exposed to X-rays
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True/False:
Duplicating film has emulsion on ONLY ONE side, & is sensitive to light |
True:
emulsion side of film appears dull |
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True/False:
sizes of dulpicating film---5x12, 8x10 AND periapical sizes |
True: three sizes of duplicating film
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Film Storage
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*protect from light,heat,moisture,chemicals,& scatter radiation
*optimum temp 50-70 degrees F *humidity levels range from 30-50% *do not keep in treatment room or near radiograph unit |
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True/False:
film Expiry date is found on box |
True:
if expired film used, xray may be fogged & not diagnostic quality...."Age Fog" |
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Processing
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steps that change latent image on film to radiograph producing a visible image
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Manual Processing Steps
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*Developer solution reduce exposed halide crystals into black silver-softens film emulsion
*Rinse, removing developer *Fixer solution removes unexposed halide crystals hardens film emulsion *(leaving film in fixer too long ie wknd, removes image from film) *wash follows fixation *dry film is final step |
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Processing Film Solutions 3 forms
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*powder
*ready to use liquid *liquid concentrante (most widely used |
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Replenish film processing solutions
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Daily & changed every 3-4 wks
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Darkroom
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*"light-tight" room where films are processed
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Light-tight
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*no light leaks present
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Light-leak
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*any white light that "leaks" into darkroom ie around door
*cause film fog |
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Safelight
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low intensity light in red-orange spectrum
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At least 4 feet away from film
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where safelight must be positioned
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Unwrapped films left too close to safelight or are exposed to safelight longer than 2-3 minutes
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appear fogged
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Good Universal safelight filter for both extraoral screen & intra oral films
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GBX-2safelight by Kodak
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Automatic Processing Tank
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divided into compartments...developer,fixer & water bath.....2 Insert tanks & 1 Master tank
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Processing Tanks Optimum temp for water
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68 degrees F (20 degrees C)
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Automatic Processor
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automates all film processing steps
requires 4-6mins develop |
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Advantages of Automatic Processor
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*less time
*time & temp auto control *less equipment *less space needed |
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Auto Processor Components
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*housing cover
*film feed slot *roller film transporter *developer compartment *fixer compartment *water compartment *dry chamber |
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True/False:
Chemical used in manual processing CANNOT be used in automatic processor |
True: DO NOT INTERCHANGE CHEMICALS
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Automatic Processor Solutions
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*check beginning of each day & replenish when necessary
*replace every 2-6 wks |
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Poor Quality Radiographs result from these errors
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*time&temp
*chemical contamination *film handling *lighting |
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Under developed film
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light appearance--developer too cool
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Overdeveloped Film
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dark appearance--developer too hot
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Reticulation of Emulsion
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cracked appearance--sudden temp change btwn developer & water
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Developer Spots
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dark or black spots-----developer contact film b4 processing
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Fixer spots
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white or light spots----fixer contacts film b4 processing
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yellow/brown stain
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yellow/brown----exhusted developer or fixer
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Developer cutoff
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straight white border
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Fixer cutoff
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straight black border
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Overlapped Films
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White or dark areas
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Air Bubbles
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white spots
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Fingernail artifact
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black crescent shaped marks
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Fingerprint artifact
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black fingerprint
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Static Electricity
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thin black branchy lines
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Scratched Film
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white lines
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Light leak
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black exposed area
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fogged film
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gray lack of detail & contrast
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