1、Designation: E 2367 05Standard Test Method forMeasurement of Nighttime Chromaticity of PavementMarking Materials Using a Portable RetroreflectionColorimeter1This standard is issued under the fixed designation E 2367; the number immediately following the designation indicates the year oforiginal adop
2、tion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers measurement of the nighttimechromaticity coordi
3、nates (x, y) of horizontal pavement mark-ings, such as traffic stripes and surface symbols, using aportable retroreflection colorimeter that can be placed on theroad delineation to measure the chromaticity at a prescribedgeometry.1.2 The entrance and observation angles of the retrorecolo-rimeter aff
4、ect the readings. As specified by the EuropeanCommittee for Standardization (CEN EN 1436), the entranceand observation angles shall be 88.76 and 1.05, respectively.1.3 This test method is intended to be used for fieldmeasurement of pavement markings but may be used tomeasure the chromaticity of mate
5、rials on sample panels beforeplacing the marking material in the field.1.4 The portable retroreflection colorimeter may integratemeasurement of the coefficient of retroreflected luminance RLaccording to Test Method E 1710 and thus be an integratedretroreflectometer/ retroreflection colorimeter.1.5 T
6、his 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.2. Referenced Docume
7、nts2.1 ASTM Standards:2D 6628 Specification for Color of Pavement Marking Ma-terialsE 284 Terminology of AppearanceE 308 Practice for Computing Colors of Objects by usingthe CIE SystemE811 Practice for Measuring Colorimetric Characteristicsof Retroreflectors under Nighttime ConditionsE 1710 Test Met
8、hod for Measurement of RetroreflectivePavement Marking Materials with CEN-Prescribed Geom-etry Using a Portable Retroreflectometer2.2 Other Standard:CEN EN 1436 Road Marking MaterialsRoad MarkingPerformance for Road Users33. Terminology3.1 The terminology used in this test method generallyagrees wit
9、h that used in Terminology E 284. The definitionsgiven in Test Method E 1710 and Practice E811apply in thistest method as well.3.2 Definitions:3.2.1 reflection colorimeter, nan instrument that illumi-nates a specimen and applies a colorimeter to the lightreflected.3.2.2 retroreflection colorimeter,
10、na reflection colorim-eter for which the illumination (influx) and reception (efflux)directions are within a few degrees of each other.4. Summary of Test Method4.1 This test method involves the use of portable retrore-flection colorimeters for determining the chromaticity coordi-nates (x, y) of hori
11、zontal coatings materials used in pavementmarkings.4.2 The entrance angle is fixed at 88.76 (co-entrance anglee of 1.24).4.3 The observation angle is fixed at 1.05 (co-viewingangle a of 2.29).4.4 The presentation angle shall be 0 (azimuthal angle b of180).4.5 The retroreflection colorimeters use one
12、 or more exter-nal panels or other instrument standards of known chromaticitycoordinates (x, y), or known spectral distribution of reflectedpower PSi.4.6 The portable retroreflection colorimeter is placed so thatthe measurement area of the retroreflection colorimeter fits1This test method is under t
13、he jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.10 onRetroreflection.Current edition approved Jan. 1, 2005. Published February 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
14、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from European Committee for Standardization, Central Secretariat(CEN), rue de Stassart 36, B1050 Brussels, Belgium1Copyright ASTM International, 100 Bar
15、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.within the width of the stripe, and the readings displayed by theretroreflection colorimeter are recorded.4.7 Readings shall be taken for the direction of traffic(supplementary azimuthal angle d of 0). Readings shall betake
16、n for each direction of traffic separately for centerlines.5. Significance and Use5.1 The chromaticity of the stripe is determined by means ofthe tristimulus values X, Y and Z for the CIE 1931 (2) standardobserver for CIE standard illuminantA, which are converted tothe chromaticity coordinates (x, y
17、) and shown in the CIE 1931(x, y)-chromaticity diagram. Refer to Practice E 308.5.2 Under the same conditions of illumination and viewing,the chromaticity coordinates (x, y) represent the nighttimecolor of pavement markings in vehicle headlamp illuminationas seen by drivers of the vehicles.5.3 The c
18、hromaticity of pavement (road) markings maychange with traffic wear and require periodic measurement toensure that the chromaticity is maintained within boundaries(see Specification D 6628 for examples of color boundaries).5.4 As specified by CEN EN 1436 and Test Method E 1710,the measurement geomet
19、ry of the instrument is based on aviewing distance of 30 m, a headlamp mounting height of 0.65m and an eye height of 1.2 m.5.5 It shall be the responsibility of the user to employ aninstrument having the specified observation and entranceangles.6. Apparatus6.1 Portable Retroreflection Colorimeter:6.
20、1.1 The retroreflection colorimeter shall be portable, withthe capability to be placed on various horizontal pavementmarkings in different locations.6.1.2 The retroreflection colorimeter shall be constructed sothat placement on the highway pavement markings will pre-clude any stray light entering th
21、e measurement area of theinstrument and affecting the reading. This may be done byshielding against stray light, or by subtraction of the stray lightreading, or both. Alternatively, the retroreflection colorimetershall produce a warning signal when stray light could affect thereading.6.1.3 For the c
22、onvenience of the user, a marking shall beplaced on the instrument to permit it to be aligned with thedirection of traffic, or the instrument design shall itself indicatethe measuring direction in an obvious manner.6.2 Light Source Requirements:6.2.1 The light source shall comply with requirements o
23、fTest Method E 1710, Light Source Requirements section con-cerning projection optics and aperture angle.6.3 Retroreflection Colorimeter Requirements:6.3.1 The retroreflection colorimeter shall demonstrate thecapability to repeatably and reproducibly measure values of thecoefficient of retroreflected
24、 luminance over the range from 100to 2000 mcdm-2lx-1to within 10 % of the assigned value. Inexceptional cases, RLvalues can be even higher, up to 3000mcdm-2lx-1.6.3.2 The retroreflection colorimeter shall provide X, Y andZ tristimulus values according to the CIE 1931 (2) colormatching functions. The
25、 retroreflection colorimeter must beable to apply illumination condition correction for CIE illumi-nant A, and may either be a tristimulus colorimeter or aspectrocolorimeter.6.3.2.1 A tristimulus colorimeter may have filters that canbe inserted individually in front of a receiver to providematches o
26、f the combined spectral distribution of the illumina-tion and the spectral responsivity of the receiver to thecombined spectral distribution of CIE illuminantAand the CIE1931 (2) x (l), y (l) and z (l) color-matching functions,respectively. The x (l) function has two distinct lobes. Thismay be dealt
27、 with by splitting x (l) into xshort(l) and xlong(l),each with a separate filter. The filters may be manually orautomatically operated.6.3.2.2 A spectrocolorimeter may measure the spectral re-flectance in equal wavelength steps covering at least thewavelength range from 400 to 700 nm, with a maximum
28、 halfpower bandwidth of 10 nm in maximum step increment of 10nm and from these data derive X, Y and Z tristimulus values.NOTE 1It is expected that a future version of this test method willinclude measurement of pavement marking chromaticity under lightingsystems other than tungsten approximating CIE
29、 standard illuminantA. Forsome of these, a 5 nanometer half power bandwidth and 5 nanometerincrement is recommended.NOTE 2Use of filters provides larger signals than measurement of thespectral distribution.6.3.3 The retroreflection colorimeter shall determine thechromaticity coordinates (x, y) for C
30、IE A and the CIE 1931Observer of white and yellow pavement markings with a valueof the coefficient of retroreflected luminance RLof 100mcdm-2lx-1, or higher, with a minimum reproducibly of 0.005in both x and y, when calibrated and used according to theinstrument manufacturers instructions.6.3.4 The
31、retroreflection colorimeter shall comply withrequirements of Test Method E 1710, Receiver Requirementssections concerning respectively receiver aperture, combinedstability of the output of the light source and receiver, andlinearity.6.4 Measurement Geometry:6.4.1 The measurement geometry shall compl
32、y with re-quirements of Test Method E 1710, Measurement Geometrysection.7. Standardization and Procedure7.1 The instrument will either require an external blackstandard or it will incorporate an internal black standard orsome other internal means of zeroing.7.1.1 If the instrument standardization re
33、quires a blackstandard then the black standard shall have virtually noretroreflection over the range of wavelengths for the visiblepart of the spectrum. The black standard may be a black glassor a light trap. For some instruments, the black standard may bean unobstructed free path obtained by a lift
34、 or a tilt of theinstrument.7.2 A portable instrument with a tristimulus colorimeter,refer to 6.3.2, can be calibrated using a black standard (ifrequired) and one, two, three or more instrument standardsconsisting of separate panels or other instruments standards.7.2.1 The instrument standard(s) sha
35、ll have known andreproducible XS, YSand ZStristimulus values measured at theE2367052same geometry as used in the portable instrument. Alterna-tively, the values of YSand the (x, y) chromaticity coordinatesmay be known instead of the tristimulus values.NOTE 3Some instruments measure RLin addition to
36、the chromaticitycoordinates (x, y), and for these instruments YSshould be in the scale ofRL.7.2.2 The producer of the instrument shall provide thesoftware needed to guide the user through the calibrationprocedure and to obtain the chromaticity values (x, y) from themeasurements.7.2.3 The accuracy of
37、 the measurement depends in particu-lar on the quality of the match of the filters described in 6.3.2.Additional factors are signal to noise ratio and other matters.7.2.4 Use of three suitable instrument standards may lead toa more accurate determination of the chromaticity of white andyellow paveme
38、nt markings than use of only one instrumentstandard. Use of more than three standards may furtherimprove the accuracy for white and yellow road markings, ormay extend the applicability of the instrument to more colors.NOTE 4A convenient choice of three instrument standards is a whitetilted reflectio
39、n standard, either without any filter in front, or covered witha yellow or an amber long pass absorption filter with pass wavelengths of515 nm and 550 nm, respectively. Such instrument standards havetypically (x, y) coordinates as shown in Fig. 1.7.3 Aportable instrument with a spectrocolorimeter, r
40、efer to6.3.2, can be standardized using a black standard (if required)and one instrument standard.7.3.1 The instrument standard shall have a spectral distri-bution of reflected power PSimeasured at the same geometry,and at the same wavelengths, as used in the portable instru-ment.7.3.2 The producer
41、of the instrument shall provide thesoftware needed to guide the user through the calibrationprocedure and to obtain the chromaticity values (x, y) from themeasurements.NOTE 5The spectrum Mbof the black standard (if required) and thespectrum Miof the instrument standard are measured, the resultingspe
42、ctrum MSi=MiMbis formed and a spectrum of calibration factors Fiis formed by Fi=PSi/MSi. When a spectrum Mihas been measured for apavement marking, the spectrum of reflected power Piof the pavementmarking is determined by Pi=Fi(MiMb). The tristimulus values X, Yand Z are determined by weighted summa
43、tions of Pi, using the spectraldistributions of CIE standard illuminant A and of the x (l), y (l) and z (l)color-matching functions, respectively, as weights.7.3.3 The accuracy of the measurement depends on wave-length accuracy, signal to noise ratio and other matters.7.3.4 Asuitable choice of the i
44、nstrument standard is a whitetilted reflection standard, which provides a fairly strong signalfor all wavelengths of the measured spectrum Mi.7.4 Note that transporting the instrument from an air con-ditioned area to the test site may result in fogging of mirrors orglass surfaces (if any) in the ins
45、trument. If there is any doubtconcerning the calibration or the readings are not constant,allow the instrument to reach ambient conditions and recali-brate with the instrument standard(s).8. Procedure8.1 Follow the manufacturers instructions for operation ofthe retroreflection colorimeter, which gen
46、erally uses the fol-lowing procedure:8.1.1 Ambient temperature shall not be less than 4C(40F).8.1.2 The surface of the marking shall be clean and dry.8.1.3 Turn on the retroreflection colorimeter, and allow it toreach equilibrium following the manufacturers instructions.FIG. 1 Example Chromaticity C
47、o-Ordinate Plot of White Standard and Test FiltersE23670538.1.4 Standardize the retroreflection colorimeter using theblack standard, if any, and the instrument standard(s) suppliedwith the instrument according to the manufacturers instruc-tions.8.1.5 For instruments with an internal reference surfac
48、e,insert that surface into the light path and read the signals fromthe display. Record these readings.8.1.6 Place the retroreflection colorimeter squarely on thepavement marking material, ensuring that the measurementarea of the retroreflection colorimeter fits within the width ofthe stripe. The rea
49、ding direction of the retroreflection colorim-eter shall be placed in the direction of traffic. Readings shall betaken for each direction of traffic separately for centerlines.8.1.7 Record the retroreflection colorimeter readings, andthen move to other locations on the sample set separatedsufficiently to provide meaningful data (typically 1 meter), andrecord the results. At intervals of one hour or less, check thestandardization according to the manufacturers instructionsand repeat standardization according to 8.1.4, if necessary.9. Test Report9
