ARBE λ* Structural Diagnostics for OBA Papers under M1/M2
A methodological whitepaper positioning ARBE λ* as an additional structural diagnostic layer for optically brightened papers in proofing and print quality control.
Atlas-bound
Valid interpretation requires a verified reference of the form Hxxx_Lxxx_Cxxx.
Not a replacement
ARBE λ* is not a replacement for ISO 13655, CIEDE2000, FOGRA/ECI, ICC workflows or visual assessment.
M1/M2 separation
M1 and M2 tracks are treated separately. Silent M1-versus-M2 comparison is invalid.
Core position
ΔE and ΔE00 describe colourimetric proximity. ARBE λ* describes atlas-bound structural drift when master, probe and measurement condition belong to a defined comparison class.
Comparison classes
Class 1: Process Drift Mode
Physical master versus physical probe. In this class, ΔΔλ* can be interpreted as a process-drift indicator when substrate family, measurement condition, instrument state and geometry remain stable.
Class 2: Reference Offset Mode
Digital atlas master versus physical probe. A large ΔΔλ* value is a diagnostic reference-family marker, not an automatic production stop.
ARBE structural attributes
| Attribute | Role |
|---|---|
| λ*_EE | Equal-energy centroid of the measured or atlas-bound spectral structure. |
| λ*_V2 | Brent-solved energetic balance point. |
| Δλ* | Internal spacing between λ*_V2 and λ*_EE. |
| ΔΔλ* | Drift indicator between probe and master. |
The ARBE λ* evaluation band is 380–730 nm. Raw measurement bands may be wider and must be reported separately.
QC interpretation
| |ΔΔλ*| | Flag | Class 1 | Class 2 |
|---|---|---|---|
| ≤ 5 nm | STABLE | Process stable; routine release may be permissible. | Minimal structural variance to reference family. |
| ≤ 10 nm | WATCH | Increase monitoring; verify process and instrument state. | Measurable material/OBA-sensitive offset. |
| ≤ 20 nm | REVIEW | Audit process, substrate, ink film, calibration and M1/M2 tracks. | Pronounced structural offset; consider physical master creation. |
| > 20 nm | BLOCK | Halt production release until reviewed. | Out-of-reference-family diagnostic marker. |
In Class 2, flags are diagnostic only and must not be used as automatic production release or rejection decisions.