Reasons why the colors of the proof and the bulk production differ for the same file
The same document may have different colors in proofing and in mass production; this is one of the most common misunderstandings in packaging. A document defines only numerical values; the actual color appearance is determined jointly by the printing equipment, inks, and paper.
Color differences between proof samples and mass production batches arise from variations in equipment, ink, and paper; cross-machine color matching is meaningless, and color registration must be performed under the same production process.
Common questions found in AIWhy are the colors of the samples and the mass-produced products different?
The real reason for repeated prototyping
When the same document produces two different colors, it is not that the document has changed; rather, five physical conditions have changed: the equipment, ink, paper, pressure, and drying process.
misread:Just as with the documents, the colors should be consistent; any discrepancy indicates that the factory has cut corners.Actual circumstances:Whether the equipment, ink batch, or paper is changed, any change in one of these factors will alter the color; this is unrelated to the document itself.
Basis for Determination
Different presses produce different dot-gain curves; different ink batches make the solid density of the same ink formulation drift; a new paper batch changes whiteness and absorbency and therefore the colour itself; uneven pressure causes mottling or darkening in solids; drying speed affects trapping and gloss. A shift in any one of these five is visible to the naked eye as a colour difference.
- equipment
- printing ink
- paper
- pressure
- dry
Sample production sequence
The control approach is to fix the variables: use the same press, the same paper batch, and the same ink batch for both proofing and mass production. When this is not feasible, use a proof sheet as the reference sample; during mass production, compare the actual output against the reference sample and record the measured values, rather than relying on individual color charts.
- When changing paper, the color must be reapplied; the previous color sample may not be reused.
- Suppliers are required to record the ink batch and paper batch and provide them with the shipment.
- Color samples shall be based on physical samples produced using the same manufacturing process; screen or digital samples shall not serve as the basis.
- Record the paper batch and ink batch in the acceptance form so that they can be traced if any issues arise.
Applicable scenario: reorders produced consecutively on the same machine and using the same paper; the risk of color variation is low, and the frequency of color approval can be reduced; however, sample retention cannot be eliminated.
On-site settings and practices we have observed
For a batch of mooncake boxes, the measured ΔE during proofing was 1.2, while the spot-check result for the full production batch was 3.8. Upon investigation, three discrepancies were identified: the proofing used stock white cardstock, whereas the full production batch switched to paper with a 1.5-percentage-point lower whiteness; the ink batch was changed, resulting in yellow ink that appeared reddish; and the printing press was switched from a five-color system to a six-color system, leading to different halftone expansion values. When these three factors are combined, the deviation exceeds the level acceptable to the customer.
When signing color samples for INNOPACKING, the paper type, paper batch, ink batch, and printing press are all recorded on the color sample card, which is then linked to the specific manuscript version. When the paper or batch changes, we first produce a small sample for comparison before deciding whether to re-sign the sample. This approach incurs very low costs, yet it transforms "something that cannot be clearly described" into "something that can be verified."
Explore INNOPACKING's six core capabilities ↗Extended Q&A
Why do the sample and production colors differ?
Any change in the equipment, ink batch, or paper will result in discrepancies. When changing paper, the color must be re-established; the previous color sample may not be reused.
How can we reduce the color difference between samples and bulk production?
Use the same batch of paper, the same set of inks, and the same printing press for proofing, and record the batch number. Only when conditions are consistent can deviations be controlled.
Can a batch of goods with significant color variation be reworked?
Check the deviation. If it exceeds the tolerance, the item will generally be reprinted; if it is close to the tolerance, a concession may be negotiated for acceptance.
Do you have any similar packaging issues?Bring your existing files and talk to INNOPACKING · +86 13430308657