LabThink Brightmeter Micro S5

LabThink Brightmeter Micro S5

Powerful. Comprehensive. User-friendly.

As the only device that measures TAPPI brightness, opacity, color, and fluorescence, the Brightimeter Micro S-5 facilitates the measurement and control of optical properties.

Designed to conform exactly to the TAPPI Official Test Methods for the pulp and paper industry, this user-friendly instrument easily replaces several individual instruments.

Measures under Illuminant C/2° Observer.
Multi-function measurement routines facilitate operation and the quick collection of data.

INTRODUCTION
A debate has raged for many years in the Paper Industry over the relative merits of measuring papetmakers' brightness utilizing instruments employing either directional or diffuse geometry. This argument stems from the fact that brightness values are dependent upon the geometry of the testing instrument used to make the measurements.

It is commonly recognized that brightness measurements made by two testers with different geometries will not agree (1). The geometry of an optical instrument refers to the physical relationship of the optical components which make up the instrument such as lamps, lenses, reflectors, apertures, etc. The two geometries most commonly used in brightness testers in the pulp and paper industry are shown.

The directional geometry referred to as 45°-0° is so called because the lamp and lens system produce a beam of light which directly strikes the sample at an angle of 45° with the perpendicular. The receiving lens system and photocell collect only the reflected light which is contained about an axis which is perpendicular to the sample (0°). This 45°-0° directional geometry is specified in TAPPI Standard T452 which further defines each geometric parameter such as size of illuminated area, viewed are:a, cone angle, etc.

Abstract
A description of the optical geometries of- the two types of brightness testers most commonly used in the Pulp & Paper Industry is presented. An historical discussion of the development and acceptance of the two types of brightness testers, one employing directional geometry and the other employing diffuse geometry, is also presented pointing out the reasons for adoption of diffuse geometry for brightness measurement by the European and Canadian Pulp and Paper Industries and adoption of directional geometry by the American Pulp and Paper Industry.

The technical and practical advantages and disadvantages of each geometry are discussed as well as their relationship to end product useage. Experimental data on several grades of paper and clay confirm the disagreement between the two standard brightness scales due to differences in illuminating and viewing geometries.

The data also substantiates the capability of instruments employing diffuse geometry to average point to point variations encountered in pulp and to minimize directionality effects encountered in embossed pulps or machine made papers. Difficulties encountered in attempting to utilize diffuse brightness testers for the measurement of fluorescent papers are discussed and documented.

ADVANTAGES AND DISADVANTAGES
One might reasonably ask why a part of the world (USA) would settle on the measurement of pulp and paper brightness by one geometry and another part of the world' (Canada and Europe) would settle on brightness measurement by a different geometry. The reason for this disagreement is that there are valid advantages and disadvantages for both the diffuse and directional geometries of brightness measurement. The following is a synopsis of the advantages and disadvantages:

Advantages of Diffuse Geometry:
1. Averages non-uniformities - This is a very important advantage in the measurement of pulp which varies greatly in its uniformity. Far fewer measurements need to be made on an instrument which diffusely illuminates the sample than on a directional reflectance instrument in order to obtain a representative average of the overall sample reflectance.

2. Averages ditectionality effects-Since the diffuse brightness tester illuminates the sample from every direction, there is no change in reading associated with sample reorientation.

3. Simulates viewing condition - Some argue that the diffuse brightness tester better simulates typical viewing conditions than the directional brightness tester. This argument pertains primarily to the fact that the area of view in the standard diffuse brightness tester is larger than the area of view in the standard directional brightness tester.

4. Excludes or includes specular gloss - A gloss trap can be either included or excluded to simulate the end product viewing conditions.

5. Minimizes translucency effect - This point also pertains to the fact that the area of illumination and view is larger in the-standard diffuse brightness tester than in the standard directional brightness tester.

Advantages of Directional Geometry:
1. Long term stability of fluorescence measurement - There is no decrease in fluorescent response due to sphere deterioration. In addition there is no change in the spectral content of the sample illumination due to spectral selectivity, of the sample itself as experienced in integrating sphere instruments.

2. Simulates end use viewing conditions - Most papers which are viewed in office or home lighting are observed under predominantly directional illumination which is simulated best by the 45°- 0° directional geometry. Also most viewers will intentionally tilt a glossy sheet to avoid seeing the gloss which again is simulated by the 45°-0° geometry.

3. Pinpoints directionality - In certain circumstances if the product is visually different when viewed in two orientations; the user may wish to have his brightness values corroborate those observations. In other words, if the eye sees a difference when a sheet is turned 90°, the instrument should measure that difference as is the case with 45-0° geometry.

4. Specular gloss is essentially eliminated - The directional geometry eliminates nearly all of the specular gloss component from the brightness reading, whereas, the gloss trap used with diffuse geometry can only partially eliminate the specular component.

We do undertake Servicing and repairing of LabThink Brightmeter Micro S5 labthink Range of products throughout india

Apart from supplying labthink Electrical Testing products in India through dealers network, catering to a variety of customers ranging from Atomic energy, Electricity Boards, Electrical Laboratory, Shopping Complexes, Shopping Mall, Electrical Contractors, Engineering Industries, Turnkey Construction Companies, Railways, Defence Installations, Research Laboratories, Educational Institutes and various Research and Development laboratories of leading national and multinational companies.

We DFT TECH, are labthink Authorized Distributors, Importers, Stockists, Dealers and Suppliers of LabThink Brightmeter Micro S5 Products in Chennai, Wayanad, Gujarat, Odisha, Rajasthan, West Bengal, Tripura, Palakkad, Kanyakumari, Theni, Krishnagiri, Namakkal, Sivagangai, Perambalur, Dharmapuri, Erode, Pudukottai and etc..