How are colours and materials checked in production?

Is the colour right? Is the board strong enough? In print and packaging production, this is not judged by eye alone but measured. Here is how colours and materials are checked and why it matters for your packaging.

Checking colours: measuring instead of guessing

Spectrophotometer: this instrument records colour objectively as numerical values. These are compared with the target value. The deviation is expressed as Delta E (ΔE). The smaller the value, the more accurately the colour matches.

Densitometer: it measures ink density, in other words how much ink has been applied. This is used to control ink coverage during printing.

Print control strips: small colour patches sit at the edge of the print sheet. They are measured without affecting the actual design. This allows solids, tints and grey balance to be checked across the whole sheet.

Standard lighting: for visual assessment, sheets are viewed under standardised light, usually in a viewing booth. That way printer and customer compare under the same conditions. Under office light or daylight, the same colour can look quite different.

Reference: the approved proof or OK sheet and, for reorders, the retained sample serve as the comparison.

The basis for all this is a defined standard such as ISO 12647. More in our article What role does colour accuracy play in printing?.

Checking materials

Depending on the project and material, different properties are checked:

• Grammage: does the material match the grade ordered?
• Thickness: it affects stability, feel and behaviour during die-cutting and folding.
• Moisture: material that is too damp or too dry can warp and cause problems in printing or folding.
• Stiffness: it determines how rigid a folding carton is.
• Surface: smoothness and whiteness affect the printed image.

Special tests for corrugated board

• Edge crush test (ECT): it shows how much pressure the corrugated board can withstand on its edge. This is important for stackability.
• Box compression test (BCT): it shows how much load a finished box can carry before it gives way.
• Burst strength: it shows how resistant the material is to concentrated pressure.

Checking processing and the finished packaging

• Creasing and folding behaviour: does the board fold cleanly without the edges cracking?
• Rub resistance: does the print withstand friction during transport?
• Gluing: does the glue seam hold under load?
• Dimensional accuracy: are the dimensions of the finished packaging correct?

A special case: food packaging

For food-contact packaging, evidence on materials and inks is added, such as suppliers’ declarations of conformity. More in our article on food packaging.

What this means for you

Measurable checks ensure that your packaging looks and works exactly as approved. This applies to the entire run and to every reorder. Read how the checks fit into the overall process in our article Quality control in the printing and packaging industry.

We print in our own production with colour management to ISO 12647. Order our free sample pack with material and print samples. You will receive a binding quote within 24 hours.

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