M0, M1 and M2 are measurement conditions, not ratings of print quality. For jewelry packaging, the practical decision is to agree one condition for the approved target and production sample, then separately agree how the finished box will be viewed. This matters most when paper, proof media, or printing contains optical brighteners, or when the finished surface changes reflectance.
Why color measurement conditions matter on a jewelry box
A spectrophotometer does not simply “read the color” of a package. It illuminates a small area, receives reflected light, and calculates color data under a stated measurement condition. The UV content of that illumination is important when a substrate contains optical brightening agents, often called OBAs.
OBAs are additives that fluoresce when exposed to UV-containing light, making a paper appear brighter or whiter. They are relevant to packaging because a white or pale board can influence the apparent character of printed brand colors. The paper white is part of the color system, not a neutral background.
Esko explains that differing UV conditions can change the measured response of brightened substrates. Measurement Conditions Compare the actual proof and production substrates before attributing a mismatch to ink alone.
Measurement conditions also do not replace visual approval. Instrument conditions describe how the device measures; viewing conditions describe the light and surroundings used by people approving a proof or final packaging. Both must be agreed. A number can identify a difference, but it cannot decide whether that difference is acceptable for a matte logo, a satin laminate, or a foil-accented rigid box.
The working difference between M0, M1 and M2
M0: a legacy reference with less-defined UV behavior
M0 uses illumination close to CIE Standard Illuminant A, with less tightly specified UV behavior. Esko cautions against exchanging M0 data for OBA-containing substrates when instrument UV behavior differs. Measurement Conditions
That does not make an existing M0 archive unusable. It means a buyer should treat it as a legacy workflow: identify the instrument and setup behind the approved standard, preserve the physical reference where possible, and avoid comparing an M0 result directly with M1 or M2 numbers as though they were interchangeable.
Choose M0 when continuity with an established, documented legacy target is the real requirement and all approvers understand that condition. Do not select it merely because an older report happens to show “M0.”
M1: D50-related illumination with controlled UV
M1 uses D50-related illumination with controlled UV so that OBA response is handled in a more defined way. It is often a sensible starting point when the approved visual workflow is based around D50-related viewing and the substrate may contain OBAs.
The important word is “starting.” M1 does not mean every M1-capable instrument will automatically produce an approval outcome that is suitable for every packaging construction. The purchaser still needs to confirm the available condition on the instrument, the proofing and production substrates, the geometry, and the visual viewing arrangement.
Techkon describes the M-series conditions as a way to standardize illumination where optical brighteners are used in substrates. Its overview identifies M1 as D50-simulating illumination with a controlled UV component. The 4 Different Measuring Mode Settings Explained
M2: UV-excluded measurement
M2 excludes UV from the measurement illumination, suppressing OBA fluorescence in that measurement. Measurement Conditions
M2 can be appropriate when stakeholders intentionally want a UV-excluded measurement basis and align their visual approval environment accordingly. It is not universally “more accurate” or inherently more premium than M1. If the retail or approval setting includes UV-containing light, an M2-only number may not describe the visual experience the buyer is trying to control.
A decision framework before proof approval
Start with the decision that matters: what physical experience is the proof intended to predict? Then use M0, M1, or M2 to make measurements comparable within that agreed path.
Ask these questions in sequence:
- Is there a legacy approved standard that must be continued? If yes, identify whether it was measured in M0, M1, or M2, and capture the actual setup rather than inferring it from an old color report.
- Could the proof paper, final wrap, or printed colorants contain optical brighteners or fluorescent components? If the answer is unknown, ask the qualified printer or paper supplier to assess the workflow. Do not assume a visually white paper is free of OBAs.
- Under what light will decision-makers examine the proof and finished packaging? Agree the relevant viewing setup before treating an instrument report as conclusive.
- Is the visible surface actually the printed surface? A laminate, varnish, film, or textured covering may alter gloss, texture, or apparent color. Measure and visually review the state that is being approved.
- Can every party use the chosen measurement condition? If a supplier’s available instrument cannot support it, resolve that before release. Switching conditions mid-project creates a new comparison, not a continuation of the original one.
Three proof failures that a mode label alone will not solve
Proof paper and final board have different OBA responses
A contract proof can appear clean and bright while the final printed paper looks warmer, or the reverse. The difference may be driven partly by paper response rather than by an obvious ink error. If a proof is meant to be the contract target, identify its paper and finish, then make the final-substrate comparison explicit.
Do not attempt a universal conversion from M1 to M2, or from M0 to M1, to make reports match. Remeasure the agreed target and sample consistently in the selected condition. A conversion may conceal the exact substrate interaction that needs a commercial approval decision.
A Delta E label masks a mode mismatch
Two reports can both include a color-difference result while using different measurement conditions, observer settings, geometries, or backing. The label does not prove that the comparison is valid. Before discussing acceptance, verify that target and sample were measured under the same declared setup.
Color-difference formula and acceptance criteria are still useful, but they are separate choices from M0, M1, and M2. The M condition sets illumination behavior; it does not select a formula, create a tolerance, or grade paper quality.
The approved proof is uncoated; the delivered surface is laminated
A printed sheet may be approved before a film, varnish, or other finishing operation changes the final visual surface. In that case, approve the pre-finish proof as an artwork or print reference only, then establish a separate review of the completed surface. A numerical match to the uncoated proof should not be treated as a promise that the laminated package will look identical.
This is especially important for dark jewelry packaging, where fingerprints, gloss variation, and edge reflections can become more noticeable. The qualified printer should choose a suitable method for the material and effect; ordinary color measurement should not be represented as a guarantee of a special-effect match.
A practical approval workflow for printed jewelry packaging
- Name the approval target. State whether the target is a contract proof, an approved press sheet, a retained production sample, or another physical reference. Include the artwork version.
- Describe the construction. Record the substrate, printed side, and whether the assessment applies before or after lamination, varnish, mounting, or wrapping. For Custom Printed Jewelry Boxes, distinguish the printed wrap from the finished assembled box when that distinction affects the visible result.
- Select and confirm the measurement condition. Choose M0, M1, or M2 for the stated purpose, then confirm it is available to the participating parties. Put the chosen condition in the approval brief, not only in an email thread.
- Lock the measurement recipe. Record instrument geometry, aperture, backing, sample side, finish state, calibration status, illuminant and observer, color-difference formula, and acceptance criteria. Also note the number and location of readings where the design has a defined measurement patch.
- Measure target and sample consistently. Calibrate as required by the instrument’s documented procedure. Measure the same type of area on each item. A textured field, a foil mark, and a smooth tint should not be silently treated as the same measurement problem.
- Perform a visual review in the agreed environment. Place the physical target and final-state sample together, using the agreed viewing conditions. Check critical brand colors, paper white, finish contrast, registration, and any visible construction transition.
- Document the release decision. Mark whether approval covers color, finish, artwork, construction, or all of them. Retain the approved reference and the measurement record so repeat orders begin with an auditable baseline.
Information to include in the buyer’s approval brief
A concise brief prevents a project manager, printer, and brand reviewer from approving different things under the same word “match.” Include:
- The exact product component being evaluated: wrap, paper bag panel, insert card, sleeve, or assembled box.
- Artwork identifier and the specified logo or color areas that are visually critical.
- Target identification and its substrate, sample side, and finish state.
- Agreed M0, M1, or M2 condition, plus instrument geometry and aperture.
- Backing method, calibration record, illuminant, observer, color-difference formula, and acceptance criteria.
- The agreed visual viewing condition and the people authorized to approve.
- A note for foil, metallic inks, embossing, texture, varnish, and laminate stating how they will be assessed.
- A clear statement of whether approval applies to a flat proof, printed sheet, or completed packaging.
Foil, metallic effects, texture and varnish need their own plan
Many jewelry brands use finishes precisely because they change with angle and light. Metallic foil, metallic inks, pearlescent effects, textured papers, embossing, debossing, and gloss varnishes complicate a single-number assessment. A reading taken at one location and orientation may be useful, but it may not represent the way an emblem catches light when a customer opens the box.
Separate the approval questions. For a metallic foil logo, define whether the priority is hue, coverage, edge sharpness, registration, reflectance, or visual uniformity. For a matte-varnish pattern over a printed tint, define which printed area is measured and which appearance attributes are judged visually. Ask the qualified printer to propose the suitable method for the specific materials; do not assume an ordinary measurement method guarantees a special-effect match.
A sensible hypothetical choice is a navy rigid box with a flat printed side panel and a gold foil monogram. The navy panel can have a documented measurement recipe. The monogram should have a separately stated visual approval criterion, since its perceived appearance depends strongly on angle, surface, and lighting.
FAQ
What are optical brightening agents in packaging paper?
They are additives that can fluoresce under UV-containing light and make paper appear brighter or whiter. Their presence can change the measured white point and influence printed-color readings, so they should be considered when selecting a measurement condition. Measurement Conditions
Is M1 always the correct choice for jewelry packaging?
No. M1 may suit an agreed D50-related, OBA-aware workflow, but the correct choice depends on the target, substrate, available instruments, and visual approval conditions. Legacy M0 or deliberately UV-excluded M2 workflows can be valid when explicitly defined.
Can we convert M0 readings to M1 or M2?
Do not rely on a universal correction. Remeasure the agreed target and production sample using the same selected condition and the same documented setup.
Does M2 make optical brighteners disappear from the paper?
No. M2 excludes UV from the measurement condition, so fluorescence is excluded from that measurement response. It does not alter the physical paper or predict every appearance under other lighting.
Does a Delta E result prove the proof and box match?
No. It is meaningful only when target and sample were measured consistently and the formula and acceptance criteria were agreed. It also cannot replace a visual assessment of finish, texture, foil, or laminate.
For a proof-and-print approval plan that reflects the actual packaging construction, discuss your project with On The Way and provide the physical target, artwork version, and proposed viewing conditions.