Professional practice, quality assurance and technical documentation
This domain asks whether you can prove the job was specified, produced and checked to an agreed standard. Documentation is the evidence; quality assurance is the system that produces it.
Documentation
- The job bag holds the approved proof, signed job ticket, production file, stock and plate records, control strips from the run and the delivery note. Without the approved proof you cannot defend a colour complaint.
- Standard operating procedures describe how the work is done; records prove it was done. Records must be legible, dated, signed and retrievable for the agreed retention period.
- Traceability runs from the delivered carton back to paper batch, ink batch, plate, press and operator.
Quality assurance
- ISO 9001 supplies the process framework: contract review, supplier evaluation, calibration, internal audit, corrective action and management review.
- ISO 12647-2 defines the offset printing condition; PSO or Fogra certification demonstrates that you hold it. ISO 12647-7 covers contract proofing.
- Calibrate densitometers and spectrophotometers on a schedule and verify against a certified reference; an uncalibrated instrument invalidates every measurement in the job.
- Non-conforming product: segregate it, record it, decide between rework, concession and rejection, then find the root cause and close the action.
Performance indicators
- Track waste percentage, on-time delivery, complaints per 1,000 jobs, first-pass yield and OEE, which is availability multiplied by performance multiplied by quality.
Worked example
Twenty solid cyan density readings from one run give a mean of 1.38 and a standard deviation of 0.02. Control limits at plus or minus three sigma are 1.32 and 1.44. A reading of 1.45 falls outside, so the run is not in statistical control even though the mean is on target: check ink feed, fountain solution conductivity and blanket torque before continuing, and record the action on the job bag. The chart alone is not evidence.
Traps that cost marks
- Filing control strips without reading them, or signing off a proof that carries no media wedge.
- Treating a corrective action as reprint and move on, with no root cause recorded.
- Writing results up after the event so the data cannot support the decision taken.