Overview
ISO 12647-9:2021 - Graphic technology - Process control for the production of half-tone colour separations, proof and production prints - Part 9: Metal decoration printing processes using offset lithography - defines process-control requirements for producing accurate offset-printed imagery on flat, white-coated metallic substrates. It addresses colour separation, proofing, production prints and associated measurement methods specific to metal decoration printing (flat sheet metal), and clarifies how this differs from paper/board workflows covered in ISO 12647-2.
Key topics and technical requirements
- Scope and substrate: Applies to flat metal sheets pre-coated with an opaque white coating (not pre-formed cans or bare metal).
- Printing condition definition: Characterization data sets, ICC output profiles or specified printing condition descriptions are required to define aims and tolerances.
- Data delivery and formats: CMYK or three-component colour data recommended; exchange via PDF/X is preferred. ICC profiles and rendering intent must be communicated.
- Proofing and conformance: Digital proofs, press proofs or OK prints should accompany job data. Conformance tests and aim values (tone curves, solids, substrate colour) are specified.
- Screening and plates: Guidance on screen frequency (ruling), plate-setter resolution (e.g., resolution to reproduce ≥150 tone value steps), dot shape/size, screen angle and tone value sum.
- Tone reproduction controls: Limits for tone value increase/spread, grey reproduction and grey balance to ensure neutrals print correctly on a white-coated metal substrate.
- Measurement methods and control strips: Procedures for computing densities, CIELAB coordinates and CIELAB differences; recommended control-strip measurements for process control.
- Spot colours: Allowed but tolerances are to be agreed between buyer and seller; spot-colour data exchange using ISO 17972 schemas is referenced.
Practical applications and users
ISO 12647-9 is essential for:
- Metal packaging printers (boxes, flat sheet metal decoration)
- Prepress and colour management specialists creating ICC profiles and characterization data
- Brand owners and specification writers who require consistent colour reproduction on metal
- Proofing houses, press operators and quality managers implementing process control and measurement routines
- Ink, plate and substrate suppliers developing compliant materials and test methods
Benefits include improved proof-to-press matching, predictable neutral/grey reproduction on white-coated metal, reduced rework and standardized communication of printing conditions.
Related standards
Keywords: ISO 12647-9:2021, metal decoration printing, offset lithography, process control, colour separations, proofing, white coated metal, ICC profile, PDF/X, tone value, screen frequency, control strip, grey balance.