T.O. 33B-1-16-75increase, decreasing the usefulness of inspection results. The radiographic film development process SHALL beperformed as close as possible to 68'F (20°C); taking into consideration chemical manufacturer's instructions. SeeTable 6-16. Film SHALL not be left in the developer solution any longer than the prescribed time for its specifictemperature. Uncontrolled time and temperature during film development causes under or over development, whichreduces or eliminates useful information from being discernible on the radiograph. Developing/processing solutionspast their useful life should be disposed of properly. Check state and local regulations to determine proper method ofdisposal.Table 6-16. Developing Time versus Temperature.Time (Minutes)Normal MaximumTemperature3-1/43-3/444-1/255-1/266-1/46-3/477-1/288-1/298076727068 (Recommended)65636.7.7.1Metol or phenodone and hydroquinone will not develop when used alone. To produce any density on the film alsorequires an alkaline solution. The alkali in effect "opens the door" and permits the developing agents to enter the poresof the emulsion. The speed with which the "door opens" is determined by the amount and potency of the alkali. If toomuch alkali is present, the developer will tend to produce chemical fog. But if too little is used, developing will beretarded. Within these limits the stronger the alkali the more rapidly development will be completed. Some of thealkali’s used in developing solutions are sodium hydroxide, potassium hydroxide, sodium carbonate, potassiumcarbonate and borax.6.7.7.1.1Developing solutions containing only the develop agents and alkali would rapidly be exhausted by oxidation from theair. The life of all developing agents are limited by (1) the reduction of silver bromide to metallic silver, and (2) theamount of oxygen absorbed by the developing agents from the air. However, there is a chemical whose inclusion indeveloping solutions extends its useful life. This chemical, sodium sulfite, and oxygen have a natural attraction foreach other. The affinity is so great that when added to a developing solution sodium sulfite actually prevents oxidationby air of the other components for limited periods of time. To assist in reducing oxidation of developing solutions thefollowing SHALL apply:a. A floating lid, that matches the general configuration of the container, SHALL be used forreplenishment and, when not in use for development; manual processing developing solutions. Thefloating lid SHALL be manufactured from a material that will not react with the processing chemistry.It should also have a specific gravity less than the chemistry so it will float naturally. One material thathas these characteristics is polypropylene. The floating lid SHALL be used in conjunction with the dustcover lid that fits over the top opening of the container.
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