Radio Graphic Film Processing

8/9/2019 Radio Graphic Film Processing

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RADIOGRAPHIC FILMPROCESSING

8/26/10 M.K. Bencharif 1

OUAIS GROUP ENGINEERING & CONTRACTING

S.A.L OFFSHORE


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FILM PROCESSING

DEVELOPERTHE DEVELOPER IS A REDUCING AGENT SUCH AS HYDROQUINONE PRESERVED IN ANALKALINE BUFFER SOLUTION. THE DEVELOPER PREFERENTIALLY ATTACKS SENSITISEDSILVER HALIDE GRAINS, REDUCING THEM TO METALLIC SILVER. IF THE FILM IS DEVELOPED ATTOO HIGH A TEMPERATURE OR FOR TOO LONG A TIME THEN UN-SENSITISED GRAINS WILLALSO BE REDUCED. THIS WILL LEAD TO A REDUCTION IN FILM CONTRAST.

ACID STOP BATHTHE STOP BATH CONTAINS ACETIC ACID. THIS RAPIDLY BRINGS TO AN END THEDEVELOPMENT PROCESS AND HELPS TO PRESERVE THE FIXER. IN SOME CASES A RUNNINGWATER WASH IS USED INSTEAD OF AN ACID STOP BATH.

FIXER / HARDENER

THE FIXER CONSISTS OF A SOLUTION OF SODIUM THIOSULPHATE IN AN ACID BUFFERSOLUTION. IT REMOVES ALL OF THE REMAINING SILVER HALIDES FROM THE FILM EMULSIONAND STABILISES THE IMAGE FORMED. THE HARDENER HELPS TO STOP THE FILM EMULSIONFROM BECOMING TOO SWOLLEN DUE TO THE EXCESSIVE ABSORPTION OF WATER. IT ALSO

HELPS TO SPEED UP THE WASHING AND DRYING PROCESSES.



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DEVELOPER

STOP BATH

FIXER

WASHINGFOR THE BEST RESULTS FILM SHOULD ALWAYS BE WASHED IN A RUNNING WATER BATH.THE TEMPERATURE OF THIS BATH SHOULD BE IN THE RANGE 5 to 25oC. OVERWASHING ORNOT WASHING ENOUGH WILL ADVERSELY AFFECT THE KEEPING PROPERTIES OF THE FILM

DRYINGAFTER WASHING AND BEFORE DRYING IT IS A GOOD IDEA TO DIP THE FILM INTO A VERYWEAK DETERGENT SOLUTION (WETTING AGENT). THIS WILL HELP THE FILM TO DRY MOREEVENLY AND QUICKLY. IT WILL HELP TO PREVENT THE FORMATION OF WATER MARKS.DRYING IS USUALLY ASSISTED BY A CIRCULATING WARM AIR HEATER. CARE MUST BETAKEN TO PREVENT AIRBORNE DUST FROM SETTLING ON THE WET FILM.


FILM PROCESSING


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TYPICAL OPTIMUM TIMES AND TEMPERATURESFOR MANUAL FILM PROCESSING

PROCESS TIME/minTEMP. 0CDEVELOPING 5

20 3262

30STOP BATH 0.520-30FIXING 2x(clearing time) 20-30

WASHING 305-10 20

13-2510> 30NOTE:WASHING TEMPERATURE > 250C TO BE AVOIDED



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GENERAL:

1. IDEALLY ALL OF THE BATHS INCLUDING THE WASH SHOULD BE AT THESAME TEMPERATURE OF ABOUT 200C. AVOIDING SUDDENTEMPERATURE CHANGES WILL PREVENT RETICULATION.

2. REPLACE CHEMICAL BATHS WHICH HAVE BECOME HEAVILYDISCOLOURED DUE TO OXIDATION.

DEVELOPER:

1. AGITATE THE FILM STRONGLY FOR THE FIRST 30 sec AND FOR 10 secPER MINUTE THEREAFTER. THIS WILL PREVENT STREAKINESSCAUSED BY UNEVEN DEVELOPMENT.

2. ALWAYS USE THE MANUFACTURERS RECOMMENDED DEVELOPMENTTIME.

3. MAINTAIN A LOG BOOK OF THE AREA OF FILM PROCESSED AND USEREPLENISHER AT THE MANUFACTURERS RECOMMENDED RATE.


GOOD PRACTICE IN AUTOMATIC FILM PROCESSING


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STOP BATH:

1. ALWAYS USE A STOP BATH. THIS WILL HELP TO EXTEND THE LIFE OFTHE FIXER AND AVOID THE POSSIBILITY OF DICHROIC FOGGING. THEADDITION OF AN ACIDITY INDICATOR TO THE STOP BATH HELPS TOMAKE SURE THAT THE BATH IS EFFECTIVE.

FIXER:1. REGULARLY CHECK THE CLEARING TIME USING SMALL SECTIONS OF

SCRAP FILM.

2. FIX ALL FILMS FOR A TIME EQUAL TO TWICE THE CLEARING TIME.AVOID FIXING FOR LONGER PERIODS THAN THIS.

3. USE HARDENER IN ACCORDANCE WITH THE MANUFACTURERSRECOMMENDATIONS. THE AMOUNT YOU NEED TO USE WILLPROBABLY BE INCREASED AT HIGH FIXER TEMPERATURES.

4. REPLENISH THE FIXER UP TO THE MANUFACTURERS RECOMMENDEDAMOUNT WHEN THE CLEARING TIME EXCEEDS SAY 2 MINUTES.




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WASHING:

1. WHENEVER POSSIBLE USE A RUNNING WATER WASH.

2. FILTER THE WASH WATER TO REMOVE ANY SOLID CONTAMINANTS.

3. AVOID WASHING AT TEMPERATURES EXCEEDING 250C.

4. WASH FILMS FOR THE OPTIMUM TIME. DONT, FOR INSTANCE, LEAVETHEM WASHING OVERNIGHT. OVERWASHING WILL MAKE THE FILMEMULSION VERY SOFT AND SUSCEPTIBLE TO DAMAGE.

DRYING:

1. USE A WETTING AGENT TO ENCOURAGE EVEN DRYING.

2. ALWAYS HANG FILMS VERTICALLY.

3. AVOID DRYING AT TEMPERATURES GREATER THAN 400C.

4. DRY FILM IN A DUST FREE ATMOSPHERE




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MAINTENANCE:

1. ALWAYS MAINTAIN THE PROCESSOR IN ATHOROUGHLY CLEAN CONDITION.

2. HAVE THE PROCESSOR SERVICED BY AN EXPERT ATREGULAR INTERVALS.

3. CAREFULLY MAINTAIN THE SUPPLY OF CHEMICALS INACCORDANCE WITH THE MANUFACTURERRECOMMENDATIONS.

4. REPLACE / CLEAN THE WATER FILTER AT REGULARINTERVALS.

5. TAKE CARE TO AVOID THE OVERLAPPING OF FILMSWHEN FEEDING THEM INTO THE ROLLERS.




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STORAGE OF UNEXPOSED FILM& GOOD DARKROOM PRACTICE

1. STORE UNEXPOSED FILM AWAY FROM (OR SHIELDED FROM) SOURCES OFIONISING RADIATION AT A TEMPERATURE OF 10-150C AND 40-60% RELATIVEHUMIDITY. AVOID CHEMICAL FUMES ESPECIALLY THOSE FROM VOLATILE

SOLVENTS. OPEN FILM BOXES ONE AT A TIME AND USE THE OLDEST FILMFIRST.

2. CHECK DARKROOM SAFELIGHT FILTERS ON A REGULAR BASIS. REPLACEDAMAGED FILTERS.

3. CHECK THE DARKROOM FOR LIGHT LEAKS ON A REGULAR BASIS.

4. KEEP THE WET AND DRY AREAS OF THE DARKROOM WELL SEGREGATED.

5. MAINTAIN THE DARKROOM IN A CLEAN AND TIDY CONDITION.

6. CHECK THE TEMPERATURE AND CONDITION OF THE PROCESSING CHEMICALSREGULARLY.

7. ALWAYS COVER THE CHEMICALS WHEN NOT IN USE TO PREVENT UNDUEOXIDATION.

8. MAINTAIN RECORDS OF THE VOLUME OF FILM PROCESSED AND REPLACECHEMICALS AT PRE-DETERMINED INTERVALS.

9. CARRY OUT REGULAR TESTS FOR THE BACKGROUND FOG LEVEL OF UN-EXPOSED FILM.



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STORAGE OF RADIOGRAPHS

THE MAJOR FACTORS AFFECTING THE LENGTH OFTIME WHICH A RADIOGRAPH CAN BE STOREDWITHOUT SERIOUS DETERIORATION ARE:

1. ADEQUATE FIXING.

2. ADEQUATE WASHING.RADIOGRAPHS WHICH HAVE BEEN PROPERLY FIXEDAND SUBJECTED TO AN OPTIMUM AMOUNT OFWASHING WILL REMAIN IN GOOD CONDITION FORMANY YEARS PROVIDED THAT THEY ARE STORED IN

MODERATE ATMOSPHERIC CONDITIONS (TYPICALLY10-250C, 40-60% RELATIVE HUMIDITY) .


GUIDE TO CORRECTING PROCESSING ARTIFACTS


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AUTOMATED PROCESSING

Artefact Cause Corrective Action

Artifacts perpendicular to the direction of film travel

Film hesitation marks plus-density lines or bands regularly or irregularly spaced

a. Chemical exhaustion orcontaminationb. Roller hesitationc. Out-of-round roller, or ahard spot or dirt on the roller

a. Adjust the rate of replenishment or mix new chemicals asnecessary. Check the replenishment tank. Check for kinkedreplenishment lines.b. Check the drive and the tension on the drive chains.c. Check the rollers in the developer rack.

Artifacts parallel to the direction of film travel

Surface drying streaks narrow wavering bands

mottled, washed out randomly spaced seen by reflected light

a. Under-replenished fixerb. Dryer is too hot

a. Increase the fixer replenishment rate.b. Set the dryer at the recommended temperature or at the

temperature required to just dry the films.

Delay streaks narrow bands (widths vary) randomly sized plus density from the leading edge through

only part of the film

Chemical build-up on thedeveloper re-wet roller

Clean the re-wet roller. Raise the solution level in thedeveloper tank.

Artifacts occurring randomly on the film surface:

Wet pressure plus density faded blotches overall graininess decreased contrast Soft emulsion scratches on the emulsion "pick-off" or "orange-peel"

Exhausted or contaminateddeveloperInadequate hardening in thefixer step

Check for kinked replenishment lines. Increase the rate of developer replenishment. Drain the developer tank and fill it with fresh chemicals. Check the condition of replenisher (age, oxidation, etc.). Increase the rate of fixer replenishment. Check for correct mixing volumes (do not dilute). Check that the fixer is not exhausted; replace with freshfixer if necessary.



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MANUAL PROCESSING

Artefact Cause Corrective ActionFaults occurring before processing:

Light streaks across one axis of the film Insertion of film in a channel-type hanger that iscontaminated with hypo. Hypo is smeared across thefilm and causes partial fixing.

Wash and dry all hangers thoroughly before re-use.

Dark spots on one side of the film Developer splashes (bad darkroom layout orprocessing techniques)

Keep the loading bench dry. Do not splash.

Light spots on one side of the film Fixer splashes (bad darkroom layout or processingtechniques)


Light spots, but usually darker than fixersplashes

Water splashes (if film is developed all at once,probably no fault will be visible)


Faults occurring during processing:

Bromide drags; flow marks. Dark areasbelow light regions or vice versa

Lack of agitation or too much aaitation Give 10 sec agitation on immersion and 5 -10 sec at thebeginning of each subsequent minute of development.

Unfixed, undeveloped, or unwashed area atthe top of the film

Failure to maintain solutions at the proper level in thetanks.

Maintain the solutions at the proper levels.

Reticulation; fine network of lines on thesurface of the film

Large temperature difference between the variousprocessing solutions.

Maintain all solutions at the recommended temperatures.

Dichroic fog; reddish brown in transmittedlight; green in reflected light

a. Contamination of developer with fixerb. Inadequate rinsec. Exhausted or non-acid fixing bath

a. Discard the contaminated solution.b. Rinse in running water.c. Use fresh acid fixing bath.

Small light spots having dark edges"punched out"

Bacterial infection of film usually, due to prolongedwashing in warm water or slow drying in a humid

atmosphere.

Avoid prolonged washing and use a good dryingcupboard.

Faults occurring during drying of the film:

Small circular light spots scattered on thesurface of the film

Air trapped on the surface of the film, not allowingdevelopment to occur; when the film is fixed, aportion of the imaae is removed.

Agitate the film well; rap sharply to dislodge air on the filmsurfaces.

Drying marks. Light areas, usually streaks,surrounded by dark edges. May bepresent on both sides of the film,but do not coincide.

Uneven drying of the gelatin, especially drops ofwater running down partially dry film. Use a good drying cabinet and dry clips for hanging films.

Do not dry films in channel-type hangers. Use a wettingagent such as KODAK PHOTO-FLO Solution.

Film buckled or areas of emulsion missing

Films sticking together during drying, followed by

forcible separation. May be due to badly designeddrying cabinet.

Use a good drying cabinet and allow adequate spacebetween the films.

8/26/10 M K Bencharif 12

Radio Graphic Film Processing

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