Color variation is the “most difficult concept to grasp” in printing: even with the same design, colors printed from different batches can differ, and clients will spot the difference immediately—if color variation isn’t managed properly, it leads to rework and disputes. This article clearly explains the key points of color variation management; clients in the packaging printing industry can refer to it as needed.
First, identify the source of the discrepancy. Sources of color variation include: printing (ink volume), paper (ink absorption), and lighting (color perception). Distinguish between “batch-to-batch” (differences between batches) and “proof-to-proof” (comparison against the approved proof) before determining a solution—batches must be consistent, and proofs must be uniform.
How to achieve color matching? Color matching (color adjustment): spot colors (Pantone numbers), four-color process (color difference values); use the “color matching reference” (approved sample) to lock in the standard. For the details of color matching, “printing to match the sample” is the guiding principle.
How to determine the light source? Light source (viewing environment): standard light source (D65), color-matching light box; “natural light” (from a window) cannot be used as a standard. Light source confirmation is based on “viewing under the light box.”
How to control batches? Batches (production consistency): ink batches (same formula), paper batches (same paper reel); retain samples from “batch division” (repackaging of bulk orders). Batch control is based on the principle of “same color within the same batch.”
How to conduct inspections? Inspection (pre-shipment): Random sampling (color difference meter / visual inspection), sample retention (for comparison); agreed-upon “color difference range” (ΔE value). Inspection details are determined by “the signed sample.”
The principles of color difference management: Establish standards for color matching, ensure fairness in lighting conditions, and maintain batch consistency—by clearly defining “what to use for comparison” and “what constitutes an acceptable difference,” disputes over color differences are reduced by half.
