BRIGHTNESS and OPACITY TESTER was developed to meet the paper industry’s needs for accurate and reliable measurement of BRIGHTNESS and OPACITY. Its design Conforms to the international standard , ISO 2469, 2470 , 2471 , SCAN- P3 & P8 , TAPPI 519 , 525, 560 , BSI 4432 pt. 1, 2, 3, CPPA E1, E2. BRIGHTNESS and OPACITY TESTER was developed to meet the paper industry’s needs for accurate and reliable measurement of BRIGHTNESS and OPACITY. Its design Conforms to the international standard , ISO 2469, 2470 , 2471 , SCAN- P3 & P8 , TAPPI 519 , 525, 560 , BSI 4432 pt. 1, 2, 3, CPPA E1, E2. SPECIFICATIONS:- Integrating spheres diameter – 15 cm. Total area of aperature in sphere- less than 7.5 % of the sphere area. Gloss Type subtends half angel of 15.5” surrounding emerging sample beam Sample aperature – circular with 34 mm diameter. Sample area of view – circular with 30 mm diameter. Accepted reflected beams – perpendicular within 00 to 10 and confined to cones of 3.5” half angles. Accuracy of ISO standards + 0.3%. Max Photometeric Linearity Error 0.1% Power Supply 230 + 5% volts, 50VA, 50 Hz. BRIGHTNESS:- ISO Brightness is the reflectance of blue light (with an affective wave length of 457nanometers) measured under carefully controlled geometric, photometric conditions. OPACITY:- ISO Opacity, in accordance with ISO standard 2471 measures with this meter directly. R0 is obtained by measuring the reflectance of a single sheet backed with a black material. R00 contained by measuring single sheet backed by multiple sheets of the same material. ISO opacity, which is the ratio R0 R0c is automatically read out by the instrument. Custom filter Selection provides accurate agreement with the ISO 2471 spectral response function at effective wave length 557 nanometer. COLOR MEASUREMENT:- Instruments measure the Tristimulus reflectance of the sample in percent by using the tristimulus filter. Brightness : Reflectance in percent with Blue filter of wavelength = 457 nm. R(x) : Tristimulus Amber (wavelength 595 nm) reflectance in percent. R(y) : Tristimulus Green (wavelength 557 nm) reflectance in percent. R(z) : Tristimulus Blue (wavelength 455 nm) reflectance in percent. From reflectance value color scale are calculated such as:- CIE Tristimulus value X, Y, Z. Color values in CIE Lx, ax, bx Or Hunter L, a , b. Dominant wavelength, Purity and Luminousity. (The symbol L, a, b are used to designate measured color value as follows: L represents lightness increasing from zero for black to 100 for perfect white; a represents redness when plus, greenness when minus, and zero for gray; and b represents yellowness when plus, blueness when minus and zero for gray).