How do you calculate a dEcmc elliptical color difference?

Follow

FAQ: "How do you calculate CMC because sometimes CMC is different of dE*?"

Based on dL*, da*, db* rectangular color differences, DE* or dE* is called a Total Color Difference. DE* is shaped like a ball or sphere centered around a target color.

A DECMC or dEcmc color difference is called an elliptical color difference is shaped like an American football centered around a target color with longest dimension along the L* axis.

A good reference document is:

ASTM D2244-15e Standard Test Method for Calculation of Color Differences from Instrumentally Measured Color Coordinates
ASTM - American Society of Testing and Materials, West Conshohocken, PA USA www.astm.org

It covers:

  • Definition of CIE L, a, b* Opponent Color Space
    Definition of dL, da, db* Color Difference Scales including delta E* Total Color Difference, delta Ecmc, delta Ecie94, delta E99 (DIN99) and delta Ecielab2000
  • Advice for measurement and reporting of Color Differences
  • Bias example of r and R in color differences between delta E* and delta Ecmc in directional 45/0 and Sphere geometries
  • Definition of Hunter L, a, b Opponent Color Difference Space
  • Definition of Hunter L, a, b and FMC-2 Color Difference Space
  • Worked examples of all color difference metrics including dE* and dEcmc and their components in Appendix A.

The worked examples are especially good for verifying color calculations and use 10 color difference pairs in different areas of color space.

Was this article helpful?
0 out of 0 found this helpful

Comments

Powered by Zendesk