QC TestsQC Tests

DarkroomDarkroom

Film processorFilm processor

V.G.Wimalasena

Principal

School of Radiography

QC tests on film darkroomQC tests on film darkroom

Safelight evaluation testSafelight evaluation test Evaluation of white light leakage and Evaluation of white light leakage and

processing area conditionprocessing area condition View box quality control testView box quality control test Evaluation of image duplicatorsEvaluation of image duplicators

Safelight testSafelight test Load a film into a cassette in complete darknessLoad a film into a cassette in complete darkness Expose the cassette with step wedge on it , using Expose the cassette with step wedge on it , using

appropriate exposure factorsappropriate exposure factors Take the film out in the darkroom and keep it on the Take the film out in the darkroom and keep it on the

darkroom bench.darkroom bench. Cover one half of the film with a cardboard.Cover one half of the film with a cardboard. Switch on the safe light and wait for 2 minutesSwitch on the safe light and wait for 2 minutes Process the film and observe for a defined line which Process the film and observe for a defined line which

divide the image into two halves.divide the image into two halves. If there is a fog, measure the optical densities and If there is a fog, measure the optical densities and

find the maximum fog (should be < 0.05) find the maximum fog (should be < 0.05)

Image of step Image of step wedge wedge

showing showing safelight fogsafelight fog

Light leakage testing and processing Light leakage testing and processing area conditionarea condition

Turn on all the lights surrounding darkroom. Enter Turn on all the lights surrounding darkroom. Enter the darkroom and switch off all the lights.the darkroom and switch off all the lights.

After eyes adapt to the dark, check for white light After eyes adapt to the dark, check for white light leaksleaks

Turn on overhead light and inspect for foreign Turn on overhead light and inspect for foreign objects, dampness etc. on counter tops & film feed objects, dampness etc. on counter tops & film feed traytray

Check the film storage conditions and processing Check the film storage conditions and processing chemical tanks.chemical tanks.

Check the room temperature.Check the room temperature.

Recommended conditionsRecommended conditions Film boxes should be stored verticallyFilm boxes should be stored vertically Temperature 14-24 Temperature 14-24 00CC Relative Humidity 30% - 60%Relative Humidity 30% - 60% Chemicals must be stored in a well-ventilated area Chemicals must be stored in a well-ventilated area

with a temperature 5-30 with a temperature 5-30 00C. (for longer periods < 21 C. (for longer periods < 21 00C) and under low lighting.C) and under low lighting.

Films and chemicals should not be stored together. Films and chemicals should not be stored together. (radioactive isotope of potassium-40 is present in the (radioactive isotope of potassium-40 is present in the chemicals and can fog the films)chemicals and can fog the films)

For films the background radiation should not exceed For films the background radiation should not exceed 7 7 µR/hr.µR/hr.

Viewbox QCViewbox QC Should be cleaned weeklyShould be cleaned weekly Intensity should be checked once a year (weekly for Intensity should be checked once a year (weekly for

mammography)mammography) Use a photometer to measure the brightness. ( luminance or Use a photometer to measure the brightness. ( luminance or

illuminance.) illuminance.) The standard luminance is 1700 nit. For mammography 3500 The standard luminance is 1700 nit. For mammography 3500

nit. (Illuminance should be above 5000 lux)nit. (Illuminance should be above 5000 lux) The colour temperature should be 5400-10,000 The colour temperature should be 5400-10,000 00K (standard K (standard

6250 6250 00K)K) Check for uniformity of the brightness compared to the centre Check for uniformity of the brightness compared to the centre

(should be within (should be within ++ 10%). 10%).

Film Copier QCFilm Copier QC

Copy a sensitometer film and compare for Copy a sensitometer film and compare for density difference( density difference( ++ 0.02). Should be done 0.02). Should be done weeklyweekly

Make a copy of the wire mesh image to check Make a copy of the wire mesh image to check the sharpness level. Should be done monthlythe sharpness level. Should be done monthly

For digital images copy a test pattern image For digital images copy a test pattern image and compare the densities from the similar and compare the densities from the similar areas.(areas.(++ 0.02) 0.02)

Processor Quality ControlProcessor Quality Control

1. 1. Solution temperatureSolution temperature Developer temperature should be checked Developer temperature should be checked

periodically through out the day. Should not periodically through out the day. Should not vary vary ++ 0.3 0.300CC

Fixer temperature should not vary Fixer temperature should not vary ++ 3 300C from C from that of the developer to avoid reticulation that of the developer to avoid reticulation marks.marks.

Use a digital thermometer with a remote probe Use a digital thermometer with a remote probe or a glass, alcohol- filled thermometeror a glass, alcohol- filled thermometer

2. Processing time2. Processing time

Change of processing time affect the image Change of processing time affect the image contrast, density and the visibility of recorded contrast, density and the visibility of recorded detail similar to that by the change of detail similar to that by the change of temperature.temperature.

Should be maintained within Should be maintained within ++ 2% to 2% to ++ 3% 3% Should be checked daily. Use a stopwatch or Should be checked daily. Use a stopwatch or

digital timerdigital timer

3. Replenishment rate3. Replenishment rate If the solutions are not adequately replenished the If the solutions are not adequately replenished the

image contrast and the optical density decreases. image contrast and the optical density decreases. Excessive replenishment has the opposite effect to Excessive replenishment has the opposite effect to some extent.some extent.

The rate should be The rate should be ++ 5% of the recommended values. 5% of the recommended values. A film and a graduated cylinder can be used to A film and a graduated cylinder can be used to

measure the rate.measure the rate. Place the cylinder under the opening of the Place the cylinder under the opening of the

replenisher line.replenisher line. With the cover of the processor open, feed a 18 x 24 With the cover of the processor open, feed a 18 x 24

cm film lengthwise, collect the chemical in to the cm film lengthwise, collect the chemical in to the cylinder and measure the volume. Divide the volume cylinder and measure the volume. Divide the volume by 24 to get the rate in milliliters per centimeter.by 24 to get the rate in milliliters per centimeter.

4 .Solution pH4 .Solution pH

Developer solutions function in a pH range of Developer solutions function in a pH range of 10 to 11.5.10 to 11.5.

Fixer solutions should have a pH between 4 Fixer solutions should have a pH between 4 and 4.5and 4.5

pH should be checked daily by using a digital pH should be checked daily by using a digital pH meter or pH paper.pH meter or pH paper.

5. Specific gravity & proper mixing5. Specific gravity & proper mixing

The chemicals should be mixed to The chemicals should be mixed to recommended concentrations. This is given by recommended concentrations. This is given by the specific gravity.the specific gravity.

Use a hydrometer to measure the specific Use a hydrometer to measure the specific gravitygravity

Developer – range from 1.07 to 1.1 and should Developer – range from 1.07 to 1.1 and should not vary by more than not vary by more than ++ 0.004 0.004

Fixer – range from 1.077 to 1.11 and should Fixer – range from 1.077 to 1.11 and should not vary by more than not vary by more than ++ 0.004 0.004

6. Processor cleaning procedures6. Processor cleaning procedures

Dirty processors cannot function properly and Dirty processors cannot function properly and is the cause of breakdown.is the cause of breakdown.

Proper cleaning procedures should be Proper cleaning procedures should be performed:performed: Daily – clean all roller racks and look for Daily – clean all roller racks and look for

malfunctioning partsmalfunctioning parts Monthly - drain the processing tanks, wash insideMonthly - drain the processing tanks, wash inside Quarterly – drain replenishment tanks and cleanQuarterly – drain replenishment tanks and clean Yearly – use system cleaners to cleen the Yearly – use system cleaners to cleen the

replenisher and circulation systemsreplenisher and circulation systems

7. Processor maintenance7. Processor maintenance

A proper maintenance schedule must be A proper maintenance schedule must be maintained to ensure continued operation of maintained to ensure continued operation of the film processor. A log of any maintenance the film processor. A log of any maintenance procedures should be kept for documentation.procedures should be kept for documentation.

Three types of maintenanceThree types of maintenance Scheduled:Scheduled:- observations, adjustments and - observations, adjustments and

replacement performed daily, weekly, monthlyreplacement performed daily, weekly, monthly Preventive:Preventive:- regular replacement of certain parts- regular replacement of certain parts Nonscheduled:Nonscheduled:- required when a system failure - required when a system failure

occurs.occurs.

8. Processor monitoring8. Processor monitoring This is accomplished with the performance of This is accomplished with the performance of

daily sensitometric tests which evaluate the daily sensitometric tests which evaluate the performance of processor systems and the performance of processor systems and the chemicals.chemicals.

Equipment requiredEquipment required Sensitometer or (step wedge and x-ray machine)Sensitometer or (step wedge and x-ray machine) DensitometerDensitometer Control chart/graph paperControl chart/graph paper FilmFilm

Processor monitoring equipmentProcessor monitoring equipment

procedureprocedure Expose the film in the sensitometerExpose the film in the sensitometer Process the filmProcess the film Measure and record the densities.Measure and record the densities. Establish the following indicators of the processor Establish the following indicators of the processor

performance.performance. Base+Fog (BF)Base+Fog (BF) – optical density of the clear portion – optical density of the clear portion Speed indicatorSpeed indicator (or mid-density point) (MD)– optical (or mid-density point) (MD)– optical

density 1 above the base+fog and that step numberdensity 1 above the base+fog and that step number Minimum densityMinimum density (or lower density) (D (or lower density) (Dminmin)– density & step )– density & step

number closest to 0.25 above B+F.number closest to 0.25 above B+F.

………….Procedure continued.Procedure continued

Maximum densityMaximum density (or high density) (D (or high density) (Dmaxmax) - the ) - the density and the step closest to 2 above B+F densitydensity and the step closest to 2 above B+F density

Contrast indicatorContrast indicator or relative density difference or relative density difference (DD) = (D(DD) = (Dmax max - D - Dmin min ))

Plot these values on a control chart.Plot these values on a control chart. Repeat the procedure daily and measure the Repeat the procedure daily and measure the

densities of the same step numbers established densities of the same step numbers established on the first dayon the first day

Look for variations and trends. Look for variations and trends.

Processor QC trouble shootingProcessor QC trouble shooting