The Hunter Rdab opponent-color scale, developed in 1943, was an early version of the Hunter L, a, b scale. Instead of L, Rd is used to designate lightness and is identical to the CIE Y Brightness/Luminosity value. Sometimes the Rd, a, b color scale is shown as LRd, aRd, bRd.
FAQ: “One question we are a little unclear about – if you set X, Y, Z on D65/10° in the Color Data View to read back the White Tile for a calibration check, will it make the YI Yellowness Index read in D65/10°, or is it fixed to C/2°?”
Density is a measurement of how thick a film layer is on a clear or opaque substrate; colorimetry is a measurement of the perception of the color of that layer.
FAQ: ” We are currently using a 10 mm path length and read in the 0 – 50 region for APHA/Pt-Co/Hazen Color, usually in the area of 10. Would you recommend a 10 mm path length with our equipment for this application?”
FAQ: “Can I use the EasyMatch QC software to import data from my MiniScan EZ or ColorFlex EZ?”
FAQ: “Do you have a formula to calculate Hunter L, a, b values from CIE L*, a*, b* values?”
FAQ: “How do I set up a Hitch Standard in the EasyMatch QC software?”
FAQ: “Our lab is having trouble losing data in EasyMatch QC jobs. Is there an AutoSave feature available in the EasyMatch QC software?”
FAQ: “Does EasyMatch QC software report peak absorbance?”
FAQ: “Can I manually enter L* a* b* values into EasyMatch QC?”