Brightness and colour: compare like with like.
Understand why R457, Ry and L* should be stated separately when specifying and comparing talc.
Use a named measurement
A single “whiteness” number is difficult to compare unless the parameter and method are stated. R457, Ry and CIELAB L* are different measurements; they should not be treated as interchangeable.
Agree how the sample is prepared
Grinding, moisture, sample presentation and measurement settings can affect optical results. Our laboratory and yours should use agreed preparation and instrument conditions when comparing the material.
Include colour coordinates where relevant
L* describes lightness. The a* and b* coordinates provide colour information that a lightness value alone does not convey. Discuss which measurements matter to your application.
Write a usable specification
Name each required parameter, its acceptance limit, the test method and preparation procedure. Retain an identified sample so comparisons can be made using the same material.
Let’s find the right talc for your process.
Share your application, specification and destination. We’ll discuss the material and sampling requirements.