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A Case for Whiteness

Did you know….color and white are not measured the same way?

COLOR

When measuring non-white colors, there are 16 indices available for measuring the color difference: DE, DL, DC, DH, MI, Color Inconstancy normally under 3 illuminants

WHITE

White, on the other hand, has the additional parameter of UV and only has 2 traditionally used indices of measurement: CIE Whiteness and CIE Tint under 1 illuminant (D65 only).

A limited number of measurement indices means less reliable visual assessment of white.

Rather than a limitation, natific saw an opportunity

natific has engineered 3 new indices for white measurement that work in complement to the existing 2. This greatly increases the ability to make adjustments and achieve the desired shade of white.

Many suppliers do not have sufficient knowledge on how to adjust white dye recipes. In developing the WhiteWarehouse, a new addition to the natific ColorWarehouse, we created a simple solution to address this knowledge gap.

White samples uploaded to the ColorWarehouse will be allocated to the WhiteWarehouse where the system will utilize all 5 whiteness indices to automatically generate recommendations for improvement. Lab managers can use this information to make the proper adjustments to achieve the correct shade of white.

The outcome of this new process has shown great lab to bulk consistency from participating mills.  

natific is helping the industry achieve the more accurate whites through our online support center, onsite training, and the WhiteWarehouse system.

Let’s take a look at a real example

A customer came to us with an issue where the CIE Whiteness and CIE Tint of a sample matched perfectly to the standard, yet the sample was metameric. We found the spectral curves to be totally different.

When the 3 new natific whiteness indices were added, it was clear that they needed to correct for bluing.

Whiteness indices of Standard and Sample:

White Standard:  CIEWhiteness: 153.06   Tint: 2.80   nWB3: 0.00     nWF3: 48.97    nWIS1: 4.01

White Sample:    CIEWhiteness: 153.29   Tint: 2.77   nWB3: 15.67   nWF3: 34.93    nWIS1: 1.17

What’s behind the numbers?

Whereas the white standard has been developed with an optical brightening agent (or OBA), the sample is based on a combination of OBA and a blue dyestuff (bluing). The OBA used for the standard has been built by an OBA with a very high green intrinsic shade (flares green with UV). The sample, on the other hand, has been built by an OBA with only a slight green intrinsic shade.

Why does it matter?

The sample shows high metamerism, which means it looks the same in D65 for most observers but different under store light and other light sources.

Only examining the CIE Whiteness and Tint indices would not have made it possible to identify the source of metamerism. Based on this analysis, natific was able to provide recommendations for adjustment.

How to achieve better whites the natific way:

  • Ensure proper UV calibration of instruments and correct settings (Spectrophotometers).
  • Ensure correct sample preparation and presentation.
  • 3 new natific whiteness indices to complement the existing CIE Whiteness indices.
  • Automatic evaluation and adjustment recommendations through the WhiteWarehouse system.

The technical team at natific also provides online and onsite support to ensure the above listed measures (and more) are properly applied by the supplier.

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