Why are color consistent charts needed for routine QC testing of opacity? Reply

Drawdown of paint sample.  Photo courtesy of BYK-Gardner.

Drawdown of paint sample on an opacity chart.
Photo courtesy of BYK-Gardner.

Opacity is an important property of architectural paint. One coat hiding reduces labor costs of a paint job and is a competitive edge in promoting paints to professionals.

During the production of paint bases, the opacity is checked by drawing down a slightly translucent wet paint film on a draw down chart. The color of the substrate (in this case the Y-value of the white and black areas of the draw down chart) needs remain constant when comparing the original draw down chart to a new box charts for accurate measuring.

Measure a paint sample with a spectro-guide spectrophotometer. Photo Courtesy of BYK-Gardner.

Measuring opacity of a paint sample with a spectro-guide spectrophotometer.
Photo Courtesy of BYK-Gardner.

If there is a difference between the white and black from chart to chart, a paint batch will show better or worse opacity and inaccurate readings. When considering the volume size of a typical paint batch, an error in the opacity measurement can be a very expensive mistake.

Quality Drawdown Chart info

To learn more about the quality of your test chart affecting your color and gloss evaluations, please click here.

For more information on Opacity and Opacity Charts, please click here.

How to do a drawdown

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