Calcium carbonate powder has a great influence on the color quality of the colorized products such as plastics and paints. Besides the whiteness and brightness, other factors including a * and b * values greatly impact Calcium Carbonate powder.

Usually, the index a * will be ideal when it is negative and as close to 0 as possible (tilt toward the Green axis). The index b * can be negative, or positive. If the value of combining these two indexes is on the left hemisphere (Green axis), the product shall have the best color quality and vice versa.

In our whiteness and brightness test result sheet, a * and b * indexes are clearly shown.

With the result of 150 samples analyzed for 5 consecutive months, Stone Base Vietnam made graphs depicting the index a * and b *, wherein a * ranged from -0.28 to 0 and b * ranged from -0.17 to 0.43. This means that the stone powder of Stone Base gives very dark quality to the production of colored products such as plastics and paints.

Distribution chart

source: Konical Minolta