How to check colour-difference deviation on press
Use the same instrument and the same backing. Measure the signed sample first, then the same place on the current sheet. Do not substitute camera RGB.
Use the same instrument and the same backing. Measure the signed sample first, then the same place on the current sheet. Do not substitute camera RGB.
The check order on press
This 5 is valid only under the agreed geometry, M condition, illuminant, and the same backing. Change any one of them and you cannot use 5 to call a pass. If these conditions do not match, do not start calling a pass.
Check against this
| Item | Do this | Do not |
|---|---|---|
| Deviation from the signed sample | Use the same instrument and the same backing. Measure the signed sample first, then the same place on the current sheet. Do not substitute camera RGB. | Write only a feeling |
| A common mistake | Do not treat ΔEab 5 as the variation allowed from sheet to sheet. Variation looks at another set of numbers, not this one. | Carry the mistake forward |
| What to keep | The report must state ΔEab, which signed sample it is against, the M condition, the geometry, and the backing. If one item is missing, do not call it a pass. | Leave only the word pass |
Check when the job changes
- First see whether the contract says deviation or variation.
- Note the geometry, the M condition, and the backing.
- Compare only two readings taken under the same conditions.
