Perceptibility and Acceptability
When assessing a color match, try not to confuse the perceptibility of a difference between a color match and a target with the acceptability of the match.
First
Is there a perceptible visual difference between the color match and target?
No! – Approve!
Yes – If acceptable: Approve!
Yes – If not acceptable: Reject!
Second
Instrumentally measure the color match versus target if specified.
Third
Correlate the visual assessment with the measurement data.
If instrumental measurements of standard and color match sample are part of the agreed upon procedures, any measurements taken should support, not substitute for, the visual evaluation. The visual judgment is the correct one.
Color measurements are an important tool by which to support visual color evaluations. However, measurements alone without visual evaluations can lead to erroneous and incorrect conclusions and decisions. Document your measurement data. For instrumental evaluations record:
- Instrument used.
- Calibration procedure.
- Illuminant selected.
- Specular component in or out (SCI or SCE).
- UV (Ultraviolet) component in or out.
- Colorspace convention used, such as L*a*b*, Lch or CMC, etc.
- Observer function (2 degree versus 10 degree).
- Sample data and comparison data to standard and specifications.
- Clear identification of sample and measured surface.
Fourth
Contact ColorXpress™ Services to relay the visual and instrumental data obtained for any requested matches. This feedback is critical in helping us to establish a correlation between our assessment methods and yours.
|