4 Darkrooms – Still Necessary? Darkrooms are necessary for manually fed processors and daylight processors.-Loading automatic film processor magazines.Necessary for conducting certain quality control tests (daily sensitometric strip).
8 Purpose of Film Processing DARKROOM FUNCTION # 2Purpose of Film ProcessingChange silver halide crystals from film emulsion (after exposure to x-ray or light photons) to black metallic silver.Latent image (invisible until processed) is developed into a Manifest image.Improper or careless processing can cause poor diagnostic quality.
13 Processing Film Table top Processors Can process as fast as 60 secondsTABLE TOP PROCESSOR
14 PROCSSING CHEMICALS Solutions are PRE- MIXED Outside Company usually provides service-Weekly or monthlySolutions should be replenished as necessary & changed regularlySolutions must be monitored (Daily QC strip).
28 Processor Chemistry Overview Developer – converts latent image into manifest imageFixer – clear the film of unexposed, undeveloped silver bromide crystals, promotes archival qualityWash – rid the film of residual chemicals
30 Developer Solution3. Hardener: prevents damage to the film from over swelling of gelatin in automatic processors.-Gluteraldehyde4. Preservative: Antioxidant that prevents oxidation of developer-Sodium Sulfite
31 Developer Solution5. Restrainer: prevents chemical fog in new developer-Potassium Bromide6. Solvent: dissolves & ionizes the developer chemicals-Water
34 Wash Rid the film of residual chemicals Residual chemicals on the film will discolor radiograph over time.Cold water processors are less efficient in removing chemicals – Warm water processors much better.Agitation during wash process is essential
39 Replenishment SystemMain function: Keep solution tanks full and assure proper solution concentration.As film is introduced into processor, sensor initiates solution replenishmentRight & wrong way to feed in film-Feed in along short edge
40 Transport System in Automatic Processors Conveys the film through different solutions (sections) by a series of rollers driven by gears, chains & sprockets.Done at a prescribed speed – determines length of time the film is in each solution
41 Temperature Regulation Main function: To control the temperature of each section of the processor.Developer – most important solution to regulateUsually between 92 degrees and 95 degreesThermostatically controlled
42 Recirculation SystemProvides agitation necessary for uniform solution concentration
43 Wash & Dryer SystemsWash: Provide thorough removal of chemical solutions from the film.-Archival film qualityDryer: Removes water from film by blowing warm, dry air-Between 120 degrees & 130 degrees F.
44 Silver RecoveryAbout ½ of the film’s silver remains in the emulsion after exposure & processing.Other ½ (unexposed silver) is removed from the film during fixing process.Silver is toxic to public water supply – must have proper disposal. Silver can be harvested from the fixer tank and recycled.
46 Darkroom Contents Loading Bench Film Bin Film I.D. Printer Safelights Pass BoxLight-tight RoomAmple ventilationWarning Light outside roomLockable DoorWall Shielding if adjacent to x-ray roomWalls painted with light color to reflect safelight