Which conditions must not be wrong when you measure hue difference
ΔH and ΔE must use the same measurement conditions. A screen that only reports ΔE cannot be used to claim ΔH passed.
ΔH and ΔE must use the same measurement conditions. An instrument screen that only reports ΔE cannot be used to claim ΔH passed.
Which conditions only count together
Do not let a pass on total colour difference stand in for a pass on hue. If hue shifts, grey is no longer grey and skin tone goes dirty. If the conditions differ, the two numbers cannot sit side by side.
Conditions
| Item | Do this | Do not |
|---|---|---|
| Hue difference | ΔH and ΔE must use the same measurement conditions. An instrument screen that only reports ΔE cannot be used to claim ΔH passed. | Only a feeling |
| Common miss | Do not let a pass on total colour difference stand in for a pass on hue. If hue shifts, grey is no longer grey and skin tone goes dirty. | Stick with the wrong call |
| What to keep | The report needs ΔH, and which colour. If you only write ΔE, do not add that hue also passed. | Only the word pass |
Check before you measure
- Confirm the report has ΔH.
- Read cyan, magenta and yellow apart.
- With no ΔH, do not write that hue passed.
