Illuminants D65 versus D65(ASTM) Follow

In the beginning, the daylight spectral power distribution function was called D65, typically either the Wyszecki or Stearns tables were used and the opponent color system was called L,a,b. As time passed improvements were made to both. To differentiate, the new D65 spectral power distribution was called D65(ASTM) and the new Lab scale was called CIELAB. To differentiate CIELAB from Hunter's LAB, astericks were added after each term. When using D65 it was important to specify whether using the original or ASTM E308 version of D65, but no convention was ever established . Fast forward twenty years and the new normal is for everyone using D65(ASTM) to just simply refer to it as D65.

HunterLab's older Universal software offered the user the choice of D65 or D65(ASTM).

Currently HunterLab's EasyMatch QC software only offers a choice named D65 which conforms to ASTM E308 (this corresponds to D65(ASTM) in the Universal software.)

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