ASTM_E_1079_-_16.pdf

Designation:E107916Standard Practice forCalibration of Transmission Densitometers1This standard is issued under the fixed designation E1079;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice2covers the calibration of transmissiondensitometers used to perform radiographic film density mea-surements(see Note 1).1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1For further information on the design and use ofdensitometers,the following literature is suggested as additional back-ground information:ISO 51:2009,ISO 52:2009,ISO 53:2009,andISO 14807:2001.2.Referenced Documents2.1 ASTM Standards:3E1316 Terminology for Nondestructive Examinations2.2 ISO Standards:4ISO 53:2009 Photography and Graphic Technology-Den-sity Measurements-Part 3:Spectral ConditionsISO 14807:2001 Photography-Transmission and ReflectionDensitometers-Method for Determining Performance3.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,see Terminology E1316.4.Significance and Use4.1 This practice provides a means for calibrating transmis-sion densitometers used for the measurement of radiographicfilm density.A transmission densitometer calibrated in accor-dance with this practice provides the assurance that accuratedensity values of radiographs are obtained.5.Apparatus5.1 Apparatus should consist of the following:5.1.1 A calibrated step tablet covering the density rangeused in production radiographs shall be used.The step tabletmay be a NIST X-ray Step Tablet(X-Ray Film Step TabletTransmission Density Standard 38100C)5,or alternately a steptablet from another supplier that is traceable to the NIST steptablet in the range provided by NIST certification.The steptablet shall have at least five step densities,which cover thedensity range that is used for production radiographs.Acalibration certificate shall be provided with the step tabletindicating the tablet ID and recorded values for each stepdensity.For suppliers of step tablets other than NIST,thecertificate shall indicate conformance of traceability to NIST,applicable ISO or ANSI standards(for example,ISO 53)used,verification of measurement on a NIST step tablet,the IDnumber of the step tablet,and calibration date of the step tablet.Precautions should be taken in the storage,handling,and use ofthe step tablet.In the event it becomes scratched,blemished,orexhibits other signs of deleterious wear,it should be replacedimmediately.The NIST(or alternate,if used)step tablet shallbe replaced four years from the date of first use.65.1.2 Transmission Densitometers,with either direct-scalereadout or digital readout displays specifically manufacturedfor the purpose of measuring the range of film densitiesdescribed in 5.1.1 may be used.5.1.3 Manufacturers Operating Instructions for Appropri-ate Transmission Densitometer.6.Calibration6.1 Full-scale linearity calibration should be performed atleast every 90 days during use as follows:6.1.1 Use the manufacturers recommended warm-up timeto stabilize circuitry before starting the calibration procedure orthe periodic verification checks described in Section 7.Adjustthe“0”reading of the densitometer after the warm-up period.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology(X and Gamma)Method.Current edition approved June 1,2016.Published June 2016.Originallyapproved in 1985.Last previous edition approved in 2010 as E1079-10.DOI:10.1520/E1079-16.2For ASME Boiler and Pressure Vessel Code applications see related PracticeSE-1079 in Section II of that Code.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.5Available from National Institute of Standards and Technology(NIST),100Bureau Dr.,Stop 1070,Gaithersburg,MD 20899-1070,http:/www.nist.gov.6Expiration interval of the NIST or alternate step tablet may be different than therequirements of this practice.Unless otherwise specified,requirements of thispractice shall apply.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.1.2 Select and measure three steps on the calibrated steptablet densities below,above,and near the midpoint of therange that is used for