Record Lab measurements, calculate ΔE76 consistently and separate measured tolerance from visual or provider acceptance.
The board calculates Euclidean distance in CIELAB as ΔE76. It is useful for a consistent internal tolerance check when the target and measured values were produced under compatible measurement conditions. A small number does not guarantee two samples will look identical under every illuminant.
Record the tolerance that actually applies to the job. A brand color, photographic proof and large-format display can have different acceptance expectations, and a provider may specify a different formula such as CIEDE2000.
When a measurement fails, keep the value in history instead of overwriting it with the corrected reading. The sequence of measurements can show whether a process adjustment improved the result and preserves evidence for later review.
A numerical difference can support tolerance tracking but does not replace viewing-condition, substrate or metamerism checks.
Comparing measurements from different instruments or illuminants can make the number misleading.
The threshold is editable because one universal ΔE limit is not appropriate for every process.