| Term | Definition |
|---|
| Why is manual film processing not usually done today? | Longer, requires more labor, and more prone to variations than automatic processing |
| What is the only manual labor required for Automatic Processing? | unloading cassette, placing film into processor, and reloading clean film. |
| What are some disadvantages to Automatic Processing? | higher costs, increased chemical fog due to higher temperatures, and possible failure of transport system. |
| What is daylight automatic processing? | Processing film without darkroom; machine does all labor. |
| What is the most common type of automatic processor, based on processing time? | 90 second |
| What different sizes of processors exist? | Floor-size, intermediate-size, and tabletop-size |
| What are the different ways a processor could be located in relation to the darkroom? | totally inside, bulk outside, bulk inside |
| Why is pH important in film processing? | Developer solution 9.5-10.7, while fixer is 4-5. Cross-contamination can lead to poor quality images. |
| What is an acidic pH? | anything below 7 |
| What is a basic pH? | anything above 7 |
| What does the developer solution (D.S.) do? | converts latent image into manifest image |
| What reaction occurs within the D.S.? | Oxidatin/Reduction reaction (Redox) |
| What is the purpose of the reaction within the D.S.? | produces darker areas on radiograph |
| What developing agents are used within the D.S. | Phenidone (light, 1.2OD) and Hydroquinone (dark, above 1.2OD) |
| What is the purpose of the developing agents in the D.S.? | Reducing agents - carry out reaction. |
| What buffer is used in the D.S.? | Na2CO3 - sodium carbonate |
| What does the buffer do in the D.S.? | swells gelatin, controls pH |
| What restrainer is used in the D.S.? | KBr - potassium bromide |
| What does the restrainer do in the D.S.? | anti-fog agent |
| What preservative is used in the D.S.? | Na2S - Sodium Sulfide |
| What does the preservative do in the D.S.? | controls oxidation (oxidation decreases OD) |
| What hardener is used in the D.S.? | Glutaraldehyde |
| What does the hardener do in the D.S.? | controls emusion swelling |
| What sequestering agents are used in the D.S.? | Chelates and Edetate |
| What do the sequestering agents do in the D.S.? | removes metallic impurities, stabilizes developer |
| What solvent is used in the D.S.? | Water |
| What is the temp of the solution of the D.S.? | 68-72F (85-105F for rapid) |
| What happens when the pH is to low or high in the D.S.? | high - excessive OD. Low - low OD (direct relationship) |
| What does the fixer solution (F.S.) do? | removes unexposed/undeveloped silver halide crystals; hardens image |
| What is the activator in the F.S.? | acetic acid |
| What does the activator do in the F.S.? | neutralizes developer |
| What does the fixing agent do in the F.S.? | removes undeveloped silver bromide |
| What is the fixing agent in the F.S.? | (NH4)2S2O3 - ammonium thiosulfate |
| What is the hardener in F.S.? | Potassium alum |
| What does the hardener do in the F.S.? | stiffens, shrinks emusion |
| What is the preservative in the F.S.? | sodium sulfite |
| What does the preservative do in the F.S.? | maintains chemical balance, assists fixing agent |
| What is the buffer/acidifier in the F.S.? | acetate |
| What is the purpose of the buffer in F.S.? | maintains acidic pH |
| What does the sequestering agent in the F.S.? | prevents development of aluminum hydroxide which can increase pH |
| What is the sequestering agent in the F.S.? | boric acids/salts |
| What is the solvent in the F.S.? | Water |
| Why is washing important? | important for archival quality of film |
| What does washing do? | removes fixer from film emusion before drying |
| What is the ideal temp for washing? | 5F BELOW developer temp |
| What organization is in charge of chemical safety? | MSDS and EPA (use and disposal) |
| What are some of the dangers of the chemicals used in developing film? | eye/skin irritant (developer); corrosive and can be absorbed (hydroquinone); skin irritant (gluteraldehyde), and can burn eyes and irritate skin due to acidic nature (fixer) |
| What does the roller subsystem do? | transports and squeegees film between tanks |
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