Radiography in Modern Industry - Kodak

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Chapter 13: Special Processing TechniquesThere are a number of special techniques useful in the processing of x-ray films. Some areapplicable to both manual and automatic processing and others only to manual. Certainradiographic installations may use one or more of these routinely; others may employ them ascircumstances warrant.Intensification Of Underexposed RadiographsEvery industrial radiographic department occasionally encounters a radiograph that has beenunderexposed, either through an oversight or because of insufficient machine capacity. If theradiograph cannot be repeated because the time required for proper exposure would beprohibitively long, or if the item is no longer available, the underexposed negative can in manycases be salvaged. Chemical intensification of the completely processed film may, under certaincircumstances, result in a speed gain of a factor of 5 to 7, while still retaining acceptableradiographic quality.Films may be intensified immediately after fixation, or after they have been fully washed anddried. In either case, the films are washed in running water for 5 to 10 minutes, hardened inKODAK Special Hardener SH-1 (formula given below), and again washed for 5 minutes.KODAK Special Hardener SH-1Avoirdupois, U.S. LiquidMetricWater 16 fl oz 500 mLKODAK Formaldehyde, about 37% solution byweight2 1 / 2 fl oz 10.0 mLKODAK Sodium Carbonate (Monohydrated) 90 grains 6.0 gramsWater to make 32 fl oz 1.0 litreThey are then treated, one at a time, for up to 10 minutes in KODAK Intensifier In-6. The workingintensifier is mixed from the stock solutions (formulas given below) by taking one part of SolutionA, and adding in succession two parts of Solution B, two parts of Solution C, and finally one partof Solution A. The order of mixing is important and should be followed. The hardening andintensification can conveniently be done in trays. The film should be agitated frequently duringintensification, after which it is washed for 20 to 30 minutes in running water and dried normally.WarningAlways add the sulfuric acid to the water slowly, stirring constantly, and never the water to theacid; otherwise, the solution may boil and spatter the acid on the hands and face, causing seriousburns.The water used for mixing the solutions for the intensifier should not have a chloride contentgreater than about 15 parts per million (equivalent to about 25 parts sodium chloride per million);otherwise, the intensification will be impaired. If in doubt as to chloride content, use distilledwater.
KODAK Quinone-Thiosulfate Intensifier In-6Avoirdupois, U.S. LiquidMetricSolution AWater 96 fl oz 750 mLSulfuric acid (concentrated) 4 fl oz 30.0 mLKODAK Potassium Dichromate(anhydrous)3 ounces 22.5 gramsWater to make 1 gallon 1.0 litreSolution BWater 96 fl oz 750 mLKODAK Sodium Bisulfite (anhydrous)1 / 2 ounce 3.8 gramsKODAK Hydroquinone 2 ounces 15 gramsKODAK PHOTO-FLO 200 Solution1 / 2 fl oz 3.8 mLWater to make 1 gallon 1.0 litreSolution CWater 96 fl oz 750 mLKODAK Sodium Thiosulfate (Hypo) 3 ounces 22.5 gramsWater to make 1 gallon 1.0 litreThe intensification may be carried out in room light. During treatment, the film may be viewed onan illuminator and the process stopped at any time that the results suit the operator.Intensification in In-6 produces a rather grainy, yellowish image, which is not quite as permanentas a properly fixed and washed silver image. However, sufficient improvement is made in theradiographic sensitivity of underexposed radiographs to make these drawbacks relatively minor.Because the intensified image is destroyed by acid hypo, under no circumstances should theintensified negatives be placed either in a fixing bath or in wash water contaminated with fixingbath. Films to be intensified should be handled as little as possible, and then only by the edges orcorners.The stock solutions from which the intensifier is mixed will keep in stoppered bottles for severalmonths, and the mixed intensifier is stable for 2 to 3 hours. The bath should be used only onceand then be discarded because a used bath may produce a silvery scum on the surface of theimage.Removal Of Fixing AgentsWhen, in manual processing, the capacity of the film washing tanks is insufficient, when timemust be conserved, or when, as in field radiography, the water supply is limited, the use ofKODAK Hypo Clearing Agent between fixation and washing is advantageous. This materialpermits a reduction of both the time and the amount of water necessary for adequate washing.After fixation, the excess fixer is removed from the film by a 30-second rinse in water. It is thenimmersed in KODAK Hypo Clearing Agent solution for 1 to 2 minutes, with agitation. With thisprocedure, the capacity of the Hypo Clearing Agent bath will be about 750 to 1000 films (8 x l0-inch) or 250 to 330 films (14 x 17-inch) per 5 gallons of solution. If no rinse is used after fixation,the capacity of the bath will be reduced to about 200 to 300 films (8 x 10-inch). The bath shouldRadiography in Modern Industry 135
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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
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Figure 49: Characteristic curves of
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Figure 51: Characteristic curve of
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Nomogram MethodsIn Figure 54, the s
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Figure 56: Transparent overlay posi
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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 and 124: 3. Age of the developer replenisher
Page 125 and 126: Figure 80: Control chart below for
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: loading-bench activities are carrie
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
Page 175 and 176: Powder Diffraction File, Internatio
Page 177 and 178: Processing TechniquesRadiographs on
Page 179 and 180: Since this formula applies only to
Page 181 and 182: such that it does not distort the i
Page 183 and 184: 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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