ASTM D7305-2008 752 Standard Test Method for Reflection Density of Printed Matter.pdf

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1、Designation: D 7305 08Standard Test Method forReflection Density of Printed Matter1This standard is issued under the fixed designation D 7305; 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 p

2、arentheses 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 describes a procedure for measuringreflection density of printed matter using a reflection densito-meter or spectrodensitometer.

3、1.2 This test method is intended primarily for process colors(yellow, magenta and cyan) and black. With appropriateinstrumentation, it may also be used for other colors.1.3 This test method applies to prints made by any printingprocess on a flat surface, with reflection density values rangingfrom ju

4、st above zero, on the unprinted substrate, through toaround 2.5 for very dense prints.1.4 This test method can be used for prints on paper, film orboard but not for those on metal or foil. It can be conducted inthe pressroom or laboratory.1.5 The values stated in SI units are to be regarded as thest

5、andard. The values given in parentheses are for informationonly.1.6 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 appli

6、ca-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 284 Terminology of AppearanceE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ANSI Standards:3CGATS.4-1993 Graphic Technology Graphic Arts Reflec-tion Den

7、sitometry Measurements Terminology, Equa-tions, Image Elements and ProceduresCGATS.6 Graphic Technology Specifications for GraphicArts PrintingCGATS.11-1999 Graphic Technology Certified ReferenceMaterials for Reflection and Transmission Metrology Documentation Requirements and Recommended Proce-dure

8、sPH 2.17 Geometric Conditions for Reflection DensityPH 2.18 Spectral Conditions for the Measurement of Opti-cal Density2.3 ISO Standard:3ISO 15790 Graphic technology and photography Certifiedreference materials for reflection and transmission metrol-ogy Documentation and procedures for use, includin

9、gdetermination of combined standard uncertainty2.4 Other Standard:3DIN 16536-2:1986 Testing of prints and printing inks ingraphic technology Colour density measurements onon-press or off-press prints3. Terminology3.1 Definitions related to appearance are in TerminologyE 284.3.2 Terminology specific

10、to this standard:3.2.1 reflection density, nthe light-absorbing property of amaterial, expressed as the logarithm of the reciprocal of thereflectance factor (i.e. higher density indicates more light isabsorbed). D = log10(1/R) = -log10(R)3.2.2 reflection densitometry, nthe practice of character-izin

11、g the amount of light absorption of materials by measuringreflectance and calculating and reporting reflection density.3.2.3 spectrodensitometer, na spectrophotometer with ap-propriate software to convert the measured reflectance valuesto reflection density.3.2.4 process color, na color having the m

12、ain attribute ofabsorbing approximately one third (1/3) the visible spectrumand transmitting the other two thirds (2/3).3.2.5 dry back, nthe reduction in density that occurs overtime after printing on paper and other absorbent substrates dueto ink penetration into the substrate.3.2.6 status T, nan I

13、SO Reflection Status Density.NOTE 1ISO Reflection Status Density is defined by its SpectralProducts (Fig. 1), that is, the wavelength by wavelength combination of astandard influx spectrum (CIE illuminant A) and the filter-modifed effluxspectrum. Originally, these modifiers were defined by combinati

14、ons ofWratten filters but today, either more durable materials, such as glass are1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.56 on Printing Inks.Current edition approve

15、d Feb. 1, 2008. Published March 2008.2For 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.3Available from American

16、 National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.used or the Spectral Products are computed numerically from tables ofweights and t

17、he spectral reflectance factors measured with a spectroden-sitometer.The status T spectral products are applicable to the measurement ofartwork for color separation and graphics arts materials such as ink-on-paper printed sheets, and off-press proofs. Status T was originally definedto closely match

18、the spectral products historically used in evaluatingoriginal artwork to be color separated but were later applied, notably in theUSA, to the measurement of most other printed graphic arts materials.The status E spectral products are also applicable to the measurement ofgraphics arts materials such

19、as ink-on-paper printed sheets, and off-pressproofs. They evolved from the wider of the two passband filter specifi-cations of DIN 16536-2:1986 for the Yellow and the Magenta and Cyanspectral products were chosen to match those of Status T. Status E spectralproducts have been applied, primarily in E

20、urope, to the measurement ofgraphic arts materials. The narrower passband of the Yellow filter(compared to Status T) produces values that are more similar for all threechromatic inks at typical printing densities.4. Symbols4.1 Symbols: The following symbols are defined or referredto in this standard

21、.D reflection densityR reflectance factor5. Summary of Test Method5.1 The densitometer or spectrodensitometer is calibratedand set for the desired spectral response and color.5.2 Multiple reflection density measurements are taken inspecified positions on the print in order to determine an averageres

22、ult.6. Significance and Use6.1 The appearance properties of printed matter, such ascolor and gloss, and performance properties such as resistanceto abrasion and chemicals, are sensitive to the thickness of theink film on the substrate. This test, which can be used in thepressroom or laboratory, prov

23、ides a convenient method formonitoring the ink film thickness equivalence among printedcolor on flat surfaces.6.2 This test can be used to help achieve consistent colorreproduction of printed color on flat surfaces.6.3 Transfer of density readings from one set of inks toanother, or from one substrat

24、e to another, carries a high risk ofproducing a color or tone shift. It is not in the scope of this testmethod to use density readings as digital proof of target pointsfor printing process control.7. Apparatus7.1 Densitometer, of which there are two types.7.1.1 Reflection Densitometer conforming to

25、ANSI Stan-dard PH 2.17 with a Status T response that conforms to ANSIStandard PH 2.18, and used according to CGATS.4-1993.FIG. 1 ISO Status Density Spectral ProductsD73050827.1.2 Spectrodensitometer, with a Status T response thatconforms to ANSI Standard PH 2.18, calibrated according tothe manufactu

26、rers instructions and used according toCGATS.6. A spectrodensitometer that gives spectral output isrequired for non-process colors.7.1.3 Standardization plate and calibration instructionssupplied by the manufacturer.8. Materials8.1 Reference Standards such as the T-Ref standard.48.2 Backing Paper fr

27、om the print job is normally used in theprinting industry. Matte-black backing paper having a visualreflection density of 1.50 6 0.20 can be used but may not beappropriate for all applications such as transparent film orpaper with low opacity, due to show through.9. Test Samples9.1 Test samples may

28、be production prints or prints pre-pared in the laboratory. Many production prints contain colorbars or targets specifically intended for monitoring reflectiondensity. In either case, the area of the specimen to be measuredmust be large enough to accommodate the aperture of theinstrument being used.

29、9.2 Print areas to be measured must be free of wrinkles,folds, fingerprints and other such defects.9.3 Prints can be measured at any interval after printing.However, on absorbent substrates the density readings willdecrease with time due to dry back until the ink is fully dry.10. Calibration and Sta

30、ndardization10.1 Warm up the densitometer or spectrodensitometeraccording to the time stated in the manufacturers recommen-dations. Use the first few readings to establish stable readingson the standardization plate.10.2 Calibrate the instrument according to the manufactur-ers procedure.10.2.1 Set t

31、he instrument to the specific density valuesestablished by the manufacturer.10.3 Further assurance of calibration precision can be ob-tained by measuring a certified reference material such as theT-Ref standard . Readings that differ from the labelled value onthe certified reference material by more

32、 than the greater of 0.02density units or 2 % should be discussed with the densitometermanufacturer in order to determine whether the particulardensitometer is performing to its design capability.11. Procedure11.1 Select the filter on the densitometer to measure thespecific color.11.1.1 If the test

33、sample is a process color, use the appro-priate status T filter.11.1.2 If the sample is black, gray or white, use the Visualdensity filter.11.1.3 If the sample is a non-process color, a spectrodensi-tometer capable of producing spectral output is used and thereading is recorded at the wavelength giv

34、ing the highestreading (maximum absorption).11.2 Set the densitometer to the appropriate mode to mea-sure density.11.3 Place the backing sheet(s) on a flat surface and the printspecimen on top of the backing sheet(s).11.4 Place the densitometer aperture on the test specimen.11.5 For laboratory and p

35、roduction prints containing largesolids, take five measurements, one in each corner 25 mm fromthe edge of the test specimen and one in the middle if the colorspecimen is large enough or five readings representative of thelength of the test specimen.11.6 For production prints containing only color ba

36、rs orsmall targets, five measurements can either be taken at theappropriate patches along the color bar or on five sequentialprints specimens.11.7 Calculate the mean and record the reading.11.8 Use the data recording requirements in Section 12 tocharacterize reflection density measurement.12. Report

37、12.1 Report the following information:12.1.1 The manufacturer and model number of the densito-meter or spectrodensitometer.12.1.2 The aperture on the measuring head of the instru-ment.12.1.3 The spectral response (status T).12.1.4 The identity of the backing paper used.12.1.5 Whether the measurement

38、 is absolute density orrelative density.512.1.6 The identity of the prints measured and the measure-ment positions.12.1.7 The interval after printing.13. Precision and Bias613.1 PrecisionAn interlaboratory study of this testmethod was conducted. Ten laboratories tested five specifiedareas of triplic

39、ate prints of four colors, measuring status Tdensities. The reflection density of the prints varied fromaround 0.85 on the yellow to about 1.60 on the black. The testresults were analyzed in accordance with Practice E 691. Basedon the statistical analysis of the results, the following criteriashould

40、 be used to judge unacceptability of results at the 95 %confidence level:13.1.1 RepeatabilityTwo results, each the mean of fivedeterminations, obtained by the same operator should beconsidered suspect if they differ by more than 0.03 densityunits.13.1.2 ReproducibilityTwo results, each the mean of f

41、ivedeterminations, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than 0.05density units.4Available from IDEAlliance, 1421 Prince St., Suite 230, Alexandria, VA223142805.5The default measurement is absolute density which includes the density of the

42、substrate. Relative density, which excludes the density of the substrate, can beobtained as a function on most densitometers or by manually measuring the densityof unprinted substrate and subtracing this value.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by

43、requesting Research Report RR: D011141.D730508313.1.3 BiasThere are several sources of bias in theassessment of reflection density of prints. A certified referencematerial (CRM) or materials are required to assess the level ofbias for any given instrument. The creation and use of certifiedreference

44、materials for assessment of printing is documented inANSI CGATS.11-1999 and ISO 15790. The industry standardreference material in the North American printing industry isthe T-Ref standard. The stated uncertainty at the 2x coveragefor the T- Ref ranges between 60.02 and 60.04 depending onthe value of

45、 the density with the most common value being60.04.An upper limit on the bias can be set as the combinationof the uncertainty of the CRM and the instrument reproduc-ibility, taken in quadrature. That is, the square root of the sumof the squares of the uncertainty and the reproducibility. Forthis sta

46、ndard the upper limit on the bias is 0.064 density units.Direct tests of T-Ref versus one of the instruments used in theround-robin gave bias of between 0.00 and 0.05 density unitson the different test targets.14. Keywords14.1 process color; reflection densitometer; reflection den-sity; spectrodensi

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