TAPPI TIPs and Test Method news.

Several new TAPPI Test Methods have been proposed in the Optical Properties subject category. Also proposed is a major revision of an existing method.

The practice of brightness/whiteness measurements in the paper industry has changed rapidly in recent years. "Brightness" values, frequently called "bright," are increasingly appearing as wrapper claims on printing and writing papers. Also becoming increasingly used in the global market are methods based on the D65 light source.

TAPPI T 452, often called "TAPPI brightness," is the method used primarily in North America, while ISO 2470, known as "ISO brightness," is used elsewhere in the world. Because the two methods use different light sources, geometries, and methodologies, different numbers are obtained. This is creating a great deal of confusion in the industry, especially with purchasing of printing and writing papers for consumer use. TAPPI currently has a brightness method, T 525, which is equivalent to the ISO method, but is currently written only for pulp, not paper. Brightness methods are the methods of choice for white papers such as printing and writing grades.

TAPPI has also developed whiteness methods based on both the TAPPI and ISO geometry: T 562 (TAPPI geometry) and T 562 (ISO geometry). ISO has a whiteness method (ISO geometry) in development.

Also of interest in the industry are methods for color. TAPPI has published color methods using both the TAPPI geometry (T 524) and the ISO geometry (T 527).

Although it would seem that the above methods would be sufficient to meet color, whiteness, and brightness measurements, in recent years addition of (non-bleach) chemical brightening agents, frequently called brighteners or fluorescent whitening agents (FWAs), has become common. Production and sale of such papers has made the use of measurement methods which can numerically compare such papers desirable. By changing the light source used in measurement instruments to a source well known in the optical industry and described as D65, the enhanced brightness or whiteness of papers to which FWAs have been added can be numerically shown and compared on, for example, ream wrappers of printing and writing papers. For TAPPI Test Methods to better meet changing global industry practice and the needs of persons using them, it is appropriate that a series of methods incorporating the D65 light source be published.

Thus, the only revision to any existing methods proposed is to T 525 (to include paper). The remainder of the proposal is to develop the following new TAPPI test methods:

* "Diffuse brightness of paper, paperboard, and pulp (d/0, D65 source)"

* "Brightness of pulp, paper and paperboard (directional reflectance at 457 nm, D 65 source)"

* "Whiteness and tint of paper and paperboard (using d/0 geometry, diffuse illumination and normal viewing, D65 source)"

* "Whiteness and tint of paper and paperboard (using 45/0 directional illumination and normal viewing, D65 source)"

* "Color of paper and paperboard (45/0 geometry, D65 illuminant)"

* "Color of paper and paperboard (d/0 geometry, D65 illuminant)"

Any TAPPI members who are interested in these new methods may join the Standard-Specific Interest Groups (SSIGs) to receive ballots when they are ready for vote. An SSIG already is formed for T 525, but any TAPPI members not currently on that SSIG are welcome to join.

If you would like to join any or all of the SSIGs for this project, please notify Charles Bohanan at TAPPI ([e-mail]) or fax at [phone]) before April 1, 2005.