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CH 20 Film Processin
Carlton/Adler Chapter 20 Film Procesing
Question | Answer |
---|---|
What are the 4 primary steps in automatic processing? | Developing, fixing, washing & drying |
What is the primary purpose of radiographic processing? | To deposit enough black metallic silver at the latent image site to permit a permanent visible image. |
What are the primary agents of the developer? | The 2 reducing agents. |
What do the reducing agents that work together do in regards to color & the speed that they work? Which process of processing are the reducing agents? | One reduction agent works slowly to produce the black areas. One reducing agent works fast to produce the shades of gray. Of the developing process. |
What does the activator do in regards to developer solution alkalinity? What chemical is the activator generally? Which process of processing is the activator? | Maintains the developer solution in alkaline state (pH 10.0-10-.5). Sodium Carbonate. Of the developing process. |
How does the activator help the reducing agents get to the silver halides? | The activator swells the gelatin making it more permeable, Therefore easier to get to the silver halides. |
What should be used to neutralize the fixer solution? | The activator or dilute warm water neutralizes fixer spills |
What is the main purpose of the restrainer? Why is this? What chemical is restrainer generally? | Providing a distraction to overactive reducers. Prevents the developer from over acting on unexposed silver halide crystals. Potassium Bromide. |
What does the developing preservative do? Which process of processing is the preservative? | Decreases the oxidation of reducing agents. Part of the developing process. |
How can the tank design for the developer solution assist in reducing developers exposure to air? | Be made long & thin, Be deep, Plastic float on surface, Cover with lid, Ping pong balls |
What does the developing hardener do? What does that do? Which process of film processing is the hardener? | Reverses the effect of the Activator (Sodium Carbonate). Controls the swelling of the gelatin. Prevents scratches & abrasions to the emulsion during processing. Maintains uniform film thickness. The developing process. |
What will too much developing hardener do? | It will harden the emulsion too soon. Prevent chemical reactions from taking place with the silver halides. |
What is used as the solvent? What should the solvent be treated for in tropical areas? Which process of film processing is the solvent? | Diluted & filtered water. For bacteria & fungi. Part of the developing process. |
What is the only solution that is drastically affected by contamination? How much % of fixer being present will stop the action of reducers? | The developer. 0.1% of fixer being present in the developer will stop the action of the reducers. |
In the process of fixing the image, what must be removed from the emulsion to permanently fix the image? What is the priomary agent in fixing? What are the other agents? | Undeveloped silver halides. The primary agent is the clearing agent, the activator, preservative, hardener & solvent. |
What does not allow unexposed silver halide crystals to be reduced to metallic silver & fog? | The restrainer |
When can film be exposed to light after the clearing agent has begun to function? What will happen to the film's appearance if fixer is not completely cleared? What do all fixer solutions used as the clearing agent? | 5-10 seconds. The films will have a milky appearance. Ammonium Thiosulfate |
Which process of film processing is the clearing agent? | The fixing of the image. |
What does the fixer activator do? Why? | Enhances the function of the clearing agent. The activator maintains acidic pH (4.05-4.5). The reducing agents in the developer solution function in an alkaline environment. Stops the action of the reducers, so there's no more reduction of silver halide. |
Why is the water kept at 5-7 degrees lower than the temp of the chemicals? | To stabilize the developer. If too cool emulsion will reticulate (film will have a crackled appearance) |
What are the purposes of the circulation system? | Stabilizing temperature, provides agitation and helps to mix the chemicals, filtering solutions |
In order from start to finish list the agents from developing then fixing/ | For developing, the reducing agents, activator, restrainer, preservative, hardener & solvent. For fixing, clearing agent, activator, preservative, hardener, solvent. |
What contains both contains a clearing and hardening agent? | The Fixer |
What controls the length of time a radiograph is immersed in each of the solutions? | The transport racks |
What are the 3 subsystems of the transport system? | Transport racks, Crossover networks & drive system. |
Where is the turnaround equipment on the transport racks? What does the master roller do? What does the planetary roller do? What do the guide shoes do? | At the top & bottom of the transport racks. Pushes the leading edge of the film against the guide shoes. Helps the guide shoes keep film in line. Keeps film from continuing on out of its path. |
What do guide shoe marks show up as on film? | As equidistant scratches or lines. |
What does the crossover rollers do? | To bend and turn the film when it reaches the transport rack. TO direct the film down to the next tank. |
In regards to the drive system, what determines how long the film is in each of the chemicals? What is the routine time? | The speed of the motor of the drive system. 90 seconds. |
What will excess water do to a film? | It will make the film sticky & possibly adhere to another film. |
What are the 2 type of replenishment? Which types of units are they used for? | Volume replenishment is used for high volume units. Flood replenishment is used for low volume units. |
How many feet from the work area should the safelights be? | 4 feet. |
Which color is the Kodak GBX filter? Which color is the Kodak Wratten series? | Kodak GBX is dark red, low intensity. The Kodak Wratten ia Orange-Bron (amber). |
What is the pro & con of the LED safelight? | Long lasting. High intial cost. |