Radiography in Modern Industry - Kodak

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Figure 79: Densitometric data for process control in industrial radiography accumulatedin accordance with the procedure described in the text. In each of the two pairs of figuresshown for each day except the first and the weekend, the top figure is the readingdetermined from the control strip exposed one or three days before--the latent-imagecontrol strip. The bottom figure is the reading determined from the control strip exposedand processed that day--the fresh-image control strip. In this example, the densitydifference is the difference between the high-density reading and the low-density readingof the fresh control strip. Latent-image control strips serve equally well for determiningdensity difference.Densitometric Data for Industrial X-ray Process ControlMon. Tues. Wed. Thurs. Fri. Sat. Sun. Mon. Tues. Wed. Thurs. Fri.High-densityreading1.95 2.121.90 1.852.15 2.001.70 1.801.95 -- -- 1.852.05 2.001.95 1.801.90 1.952.05 1.952.00Low-densityreading0.82 0.910.71 0.741.03 0.900.61 0.640.80 -- -- 0.801.01 0.970.92 0.720.80 0.880.95 0.750.80Densitydifference1.13 1.19 1.12 1.09 1.15 -- -- 1.04 1.03 1.10 1.10 1.20Radiography in Modern Industry 124
Figure 80: Control chart below for one exposing unit and one processor showingvariations in exposure and processing. The control limits are wider than if either exposureor processing were monitored individually. Plot all the high-density readings, but connectonly the readings from control strips exposed at the same time. The connecting linesrepresent the day-to-day repeatability of film processing; the difference between pointplots on a given day represents the repeatability of exposure.Process Control Chart--Exposure and Processing VariationsMon. Tues. Wed. Thurs. Fri. Sat. Sun. Mon. Tues. Wed. Thurs. Fri.UppercontrollimitProcessdensityaimLowercontrollimit2.151.951.75Process Control TechniqueCertain measures can be taken to reduce radiographic process variability, but they dependlargely on the conditions and the requirements of the individual user. This is particularly true withrespect to variations introduced by the exposing unit. Obvious causes of exposure variability,such as fluctuations or changes in line voltage, must first be eliminated, of course. The followingmay be of help in reducing variations in density attributable to processing of the film in anautomated processor.Use the electronic thermometer with the submersible stainless steel probe to set the temperatureof the developer. Use it to check for fluctuations in developer temperature; the thermostat for thedeveloper may allow the temperature to vary by 2°F. Procedures and thermostats that will holdthe temperature of the developer to ±1/5°F are available.Use a graduate frequently to check and to maintain the developer replenisher rate at thatrecommended for the average film density in the process.Keep processing of completely exposed film or completely unexposed film to a minimum.Developer that is overreplenished generally causes an increase in film densities; developer that isunderreplenished generally causes a decrease in film densities. When the stage ofunderreplenishment reaches a certain point, the rate at which film densities decrease maybecome quite rapid.Never permit the developer replenisher to age beyond its recommended storage life. If thedeveloper replenisher exceeds its storage life, the storage tank should be emptied and rinsed anda fresh solution should be prepared. Do not mix fresh developer replenisher with a solution that isnear the limit of its recommended storage life.Do not replenish with developer replenisher that is past its recommended storage life. Do notreplenish with oxidized developer replenisher. The results of these practices can be losses indensity, a shift in contrast, or both.Use fresh solutions at the time a process control system is initiated to reduce the possibility ofestablishing a process density aim base on a process that is abnormal.When the processed control strips indicate an out-of-control condition, check for an obvious error,such as the temperature of the developer (if a film processing error is indicated), or the techniqueRadiography in Modern Industry 125
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RadiographyinModernIndustry
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RadiographyinModernIndustryFOURTH E
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ContentsIntroduction...............
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Chapter 1: The Radiographic Process
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Intensifying ScreensX-ray and other
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makes it a very suitable material f
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Figure 6: Typical voltage waveforms
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Table I - Typical X-ray Machines an
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The wavelengths (or energies of rad
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Table III - Industrial Gamma-Ray So
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1. The source of light should be sm
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B and H in the Figure 13 show the e
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Figure 14: Geometric construction f
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Figure 17: Pinhole pictures of the
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The kilovoltage applied to the x-ra
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Figure 21: Schematic diagram of som
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kind of material radiographed, the
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instance, the kilovoltage may be fi
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The technique need not be limited t
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Chapter 5: Radiographic ScreensWhen
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Contact between the film and the le
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Figure 29: The number of electrons
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lead foil screens ran be retained w
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Figure 33: The sharpness of the rad
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Figure 34: Low density (right) is a
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such as a wall or floor, on the fil
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from this source. Since scatter als
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A filter reduces excessive subject
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Definite rules as to filter thickne
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0.010-inch front screen of value be
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Example: Suppose that with a given
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If the milliamperage remains consta
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espectively. In other words, a cons
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Any given exposure chart applies to
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Figure 46: Typical gamma-ray exposu
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where the slope of the characterist
Page 73 and 74: Figure 49: Characteristic curves of
Page 75 and 76: Figure 51: Characteristic curve of
Page 77 and 78: Nomogram MethodsIn Figure 54, the s
Page 79 and 80: Figure 56: Transparent overlay posi
Page 81 and 82: Figure 58: Overlay positioned so as
Page 83 and 84: The problem of radiographing a part
Page 85 and 86: Figure 62: System of lines drawn on
Page 87 and 88: Chapter 8: Radiographic Image Quali
Page 89 and 90: Film contrast refers to the slope (
Page 91 and 92: Hole Type PenetrametersThe common p
Page 93 and 94: of the same thickness as the specim
Page 95 and 96: Chapter 9: Industrial X-ray FilmsMo
Page 97 and 98: Figure 70 indicates the direction t
Page 99 and 100: the lead letters on a radiation-abs
Page 101 and 102: Therefore, protection requirements
Page 103 and 104: 5. Avoid pressure damage caused by
Page 105 and 106: Paddles or plunger-type agitators a
Page 107 and 108: slow, and the development time reco
Page 109 and 110: ubbles make their way to the surfac
Page 111 and 112: When development is complete, the f
Page 113 and 114: soften considerably with prolonged
Page 115 and 116: Figure 77: The roller transport sys
Page 117 and 118: Rapid Access to Processed Radiograp
Page 119 and 120: Figure 78: Film-feeding procedures
Page 121 and 122: Chapter 11: Process ControlUsers of
Page 123: 3. Age of the developer replenisher
Page 127 and 128: DiscussionDensitometric data and pr
Page 129 and 130: Figure 82: Plan of a manual x-ray p
Page 131 and 132: Figure 83: A schematic diagram of a
Page 133 and 134: loading-bench activities are carrie
Page 135 and 136: KODAK Quinone-Thiosulfate Intensifi
Page 137 and 138: Methylene-Blue MethodTwo variations
Page 139 and 140: KODAK Hypo Test Solution HT-2Avoird
Page 141 and 142: In summary, use of the test papers
Page 143 and 144: narrow angle would be very thick, e
Page 145 and 146: When radiation passes through a spe
Page 147 and 148: Figure 89: Demonstration of the eff
Page 149 and 150: Figure 90: The amount of gamma radi
Page 151 and 152: The radiograph exposed in the right
Page 153 and 154: To illustrate, let us assume that t
Page 155 and 156: Figure 95: High-speed x-ray picture
Page 157 and 158: Figure 97: Two methods of neutron r
Page 159 and 160: Duplicating RadiographsSimultaneous
Page 161 and 162: Sometimes, as when sets of referenc
Page 163 and 164: PhotofluorographyIn photofluorograp
Page 165 and 166: discontinuities or of segregation i
Page 167 and 168: from the camera or by reaching down
Page 169 and 170: Figure 106: Schematic diagram of th
Page 171 and 172: valuable technique, for instance, i
Page 173 and 174: The position of the spots is determ
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Powder Diffraction File, Internatio
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Processing TechniquesRadiographs on
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Since this formula applies only to
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such that it does not distort the i
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Figure 113: A: Representation of a
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Figure 115: Characteristic curve of
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film fairly well. If high densities
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Density = 1.5 Density = 2.5Film Rel
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In most industrial radiography, the
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e noted here. Although the average
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Chapter 17: Film Graininess; Signal
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The ratio of signal to noise has a
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Chapter 18: The Photographic Latent
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Thus, the change that makes an expo
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Figure 130: Stages in the developme
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electrons by successive Compton int
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Development is essentially a chemic
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Chapter 19: ProtectionOne of the mo
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duct is brought into the x-ray room
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Radiography in Modern Industry - Kodak

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