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Delta E Color Difference for Quality Control –
Anodized Gold Metal Parts

We manufacture many of our products with vibrantly colored anodized metal enclosures.  Our light sources are bright gold and all incoming parts are tested to meet our color standard. With this quality control process, all of our light sources will always have the same golden color.  We use the StellarRAD+Color to measure the perfect gold sample.  Then we can record its CIE L*a*b* color values and load the saved sample as a reference (2 software clicks!).  Now every incoming sample can be tested against it and we can calculate the delta E color difference value (dE) for each new test sample. Typically a dE greater than 3 is considered a different color.  dEs less than 6 are indistinguishable to the human eye and dEs larger than 10 are normally rejected as a faulty batch.  In this example, you can see a passing sample with dE= 0.95 and also rejected panels measuring 10.35 and 13.01.