ANSI T 525 OM-2012 Diffuse brightness of paper paperboard and pulp (d 0) - ultraviolet level C.pdf
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1、T 525 om-12 SUGGESTED METHOD 1972 HISTORICAL METHOD 1985 OFFICIAL TEST METHOD 1986 REVISED 1992 REVISED 2002 REVISED 2006 REVISED WITH TITLE CHANGE 2012 2012 TAPPI The information and data contained in this document were prepared by a technical committee of the Association. The committee and the Ass
2、ociation assume no liability or responsibility in connection with the use of such information or data, including but not limited to any liability under patent, copyright, or trade secret laws. The user is responsible for determining that this document is the most recent edition published. Approved b
3、y the Standard Specific Interest Group for this Test Method TAPPI CAUTION: This Test Method may include safety precautions which are believed to be appropriate at the time of publication of the method. The intent of these is to alert the user of the method to safety issues related to such use. The u
4、ser is responsible for determining that the safety precautions are complete and are appropriate to their use of the method, and for ensuring that suitable safety practices have not changed since publication of the method. This method may require the use, disposal, or both, of chemicals which may pre
5、sent serious health hazards to humans. Procedures for the handling of such substances are set forth on Material Safety Data Sheets which must be developed by all manufacturers and importers of potentially hazardous chemicals and maintained by all distributors of potentially hazardous chemicals. Prio
6、r to the use of this method, the user must determine whether any of the chemicals to be used or disposed of are potentially hazardous and, if so, must follow strictly the procedures specified by both the manufacturer, as well as local, state, and federal authorities for safe use and disposal of thes
7、e chemicals. Diffuse brightness of paper, paperboard and pulp (d/0) ultraviolet level C 1. Scope 1.1 This method is for the determination of the brightness of white, near-white, and naturally colored pulp, paper, and paperboard. Brightness is a commonly used industry term for the numerical value of
8、the reflectance factor of a sample with respect to blue light of specific spectral and geometric characteristics. This method requires an instrument employing diffuse illumination and 0 viewing geometry 1.2 This method is applicable to all naturally-colored pulps, and papers and board made therefrom
9、. The measurement is not suitable for paper or paperboard containing added coloring matter (such as yellow or green dyestuff) which appreciably absorbs light in that part of the spectrum extending from about 400 to 500 nm. This brightness method is not applicable to colored papers. 1.3 Pulps to be t
10、ested shall be made into handsheets prepared according to TAPPI T 218 “Forming Handsheets for Reflectance Tests of Pulp (Bchner Funnel Procedure)” or T 272 “Forming Handsheets for Reflectance Tests of Pulp (Sheet Machine Procedure).” This method can also be used to measure the brightness of machine-
11、dried sheets. NOTE 1: The brightness of a handsheet will usually be 0.5 to 1.0 units higher than that of a machine-dried sheet made from the same pulp. 1.4 This method utilizes an integrating sphere to provide diffuse illumination and perpendicular (0) observation geometry (1) designated in optical
12、terminology as d/0. With this geometry, specimen surface structure and azimuthal orientation have a negligible effect on brightness. 1.5 The instrument has a relatively large specimen aperture for the purpose of averaging small area variations in reflectance, making it possible to obtain a reliable
13、average value with only a few individual measurements. 1.6 This method is not intended for use with colored materials. T 525 om-12 Diffuse brightness of paper, paperboard and pulp (d/0) / 2 2. Summary Diffuse reflectance is measured in the wavelength range of 400-520 nm with an effective wavelength
14、of 457 nm by using a suitable filter set or an equivalent device for modifying the spectral response and an instrument having diffuse illumination and perpendicular observation geometry. The measurements are made in terms of absolute reflectance factors. 3. Significance 3.1 Blue-light reflectance me
15、asurements were originally designed to provide an indication of the amount of bleaching that has taken place in the manufacture of pulp. The higher the blue-light reflectance, generally the whiter the products will appear. In recent years, the method has been extended to white and near-white paper a
16、nd paperboard, and is suitable for that purpose. The method provides a simple, single-number index useful for comparing similar white materials; however, colored materials are better identified by using a standardized three-dimensional color space see TAPPI T 524 “Color of Paper and Paperboard (45/0
17、 Geometry)” and T 527 “Color of Paper and Paperboard (d/0 Geometry)”. 3.2 Because the instrument geometry of this method is different from that of TAPPI T 452 “Brightness of Pulp, Paper and Paperboard (Directional Reflectance at 457 nm),” there is no simple relationship between the two brightness sc
18、ales (3). 3.3 Specularly reflected light (gloss) is excluded from the measurement of diffuse brightness by the use of a gloss trap (specular reflectance absorber) as required in 5.1.1.3. NOTE 2: Material containing fluorescent brightening agents will exhibit higher reflectance values to a degree whi
19、ch is dependent upon the ultraviolet (UV) content of the radiation incident on the specimen. Control of such UV content is essential to maintain continuity of measurement among optically brightened pulps. This method specifies that the level of UV excitation correspond to the equivalent level of CIE
20、 Illuminant C. NOTE 3: No known material is both perfectly reflecting and perfectly diffusing, but standards can be calibrated in terms of absolute reflectance factors (2,4). Standards with calibrations based on this reference can be obtained from Calibration Laboratories1, as defined in Section 5.3
21、 of TAPPI T 1211 “Acceptance Procedures for Calibration Laboratories.” 4. Definitions 4.1 Diffuse reflectance factor, the ratio of the radiance factor of a specimen to that of a perfectly reflecting diffuser, each being irradiated and viewed identically (4). 4.2 Absolute brightness, the diffuse refl
22、ectance factor for blue light in terms of a perfectly reflecting, perfectly diffusing specimen as determined on an instrument as described in Section 5. 4.3 Perfect reflecting diffuser, the ideal reflecting surface that neither absorbs nor transmits light, but reflects diffusely, with the radiance o
23、f the reflecting surface being the same for all reflecting angles, regardless of the angular distribution of the incident light. 5. Apparatus 5.1 Reflectometer1, an instrument designed for the measurement of diffuse reflectance which employs the following geometric, photometric, and spectral charact
24、eristics: 5.1.1 Geometric characteristics 5.1.1.1 One or more light sources direct light into an integrating sphere which provides diffuse illumination of the specimen. The integrating sphere has an inside diameter of 150 mm and is coated with a matte white paint with absolute reflectance of 96 or g
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