Presentation on theme: "Manual Film Processing Clifford R. Berry, DVM Adjunct Associate Professor, University of Tennessee Veterinary Specialists Center, Maitland, FL ACVR Artifacts."— Presentation transcript:
Manual Film Processing Clifford R. Berry, DVM Adjunct Associate Professor, University of Tennessee Veterinary Specialists Center, Maitland, FL ACVR Artifacts
Manual Film Processing Manual film processing involves dipping the exposed film into tanks of developer, fixer and wash. The chemical are held in stainless steel tanks. The water should be running and draining. Temperature of developer and fixer must be known for adequate development.
Manual film processing DeveloperFixer
Developer Chemical must be stirred before submerging the film into the chemicals or there will be heterogeneous development of the film. Stirrers should be kept separate.
Developer Time-Temperature technique. 68 0 F = 5 minutes. A mechanical timer with a bell is used to time the duration of development and fixing since the room will be dark
Film Hanging The films are placed on hangers to hold the films within the tank. Metal clips poke through the film in order to hold onto the film. Be sure that films are not touching. If developing multiple films, beware of safety light fog.
Manual Film Processing The edges of the film will be punctured by the hanger and can be used to identify manual processed films. Film corners may be cut. Seen on all four corners.
Manual Film Processing The films can be air dried Dryers are available to speed the process of drying films
Manual film processing Tanks should be covered when not in use to prevent the developer from oxidizing. Chemical should be replaced on a regular basis.
Film Too Light Underdeveloped Exhausted Chemistry Underexposed
Manual Film Processing Exhausted Developer Developer time has to increase to due oxidized developer and with prolonged contact with the developer chemical all crystals (exposed and unexposed) are reduced results in poor contrast.
Common Artifacts Associated with Film Processing Low fixer level The entire film was developed but the top portion was not fixed or cleared.
Chemistry Levels Uneven/Low Low developer and fixer level The top of the film was never fixed or developed
Low developer and Fixer (higher level than developer) The green strip at the top is the portion of the film not developed or fixed Chemistry Levels Uneven/Low
Development - Kiss Artifact Cleared emulsion on reflected light. Matching radiograph to accompany
Fixer - Kiss Artifact Developed but emulsion not cleared so “milky” or colored appearance (sheen) still present at place where two films where in contact within the fixer.
Emulsion Wrinkle/Peel Emulsion wet enough that peels away from the film base.
Lack of Wash - Fixer Oxidation Formation of Silver Sulfide
Debunking Solarization Solarization - Process for making copy films by overexposure such that a reversal of optical densities are produced when exposed to light. Rebromination hypothesis considered likely explanation at this time. Optical reversal occurs after prolonged exposure of the film so that there is a reversal of the H & D curve. Correct manual processing artifact = Sabatier Effect
Sabatier Effect White light exposure of the radiograph while in the developer (manual processing). Results in the silver grains in the areas that are “white” non-exposed becoming developed to Dmax. The partially developed areas are less affected by the light exposure. Creates characteristic lines of demarcation called “Mackie lines.”
Incomplete fixation Colored Film Pink – on view box Greenish with reflected light Due to exhausted fixer, incomplete fixation or insufficient rinsing
Non Stirred Developer
Developer - Specific Gravity Effects Developer Specific Gravity will cause the “strongest”, non oxidized developer to settle to the bottom of the developer tank.
Film Fog - Safety Light Manually processed. Light leak or inappropriate safe light in dark room. Note the shadow (minus density) created by the film hanger.