What is a CRPC, and which one fits coated board
A CRPC is a measured reference printing condition, one line from newsprint to high-white coated paper. Do not assume coated board is CRPC6. Measure paper white first: near GRACoL 2013, about L* 95, a* 1, b* −4, then CRPC6. Yellower or darker paper uses the customer’s data set. Do not force it.
A CRPC is a measured reference printing condition, one line from newsprint to high-white coated paper. Do not assume coated board is CRPC6. Measure paper white first: near GRACoL 2013, about L* 95, a* 1, b* −4, then CRPC6. Yellower or darker paper uses the customer’s data set. Do not force it.
Paper white decides whether this line fits
CRPC6 stands for a reference on high-white coated paper, not “any coated stock”. Board coating and the furnish pull paper white yellow and dark. Match that white to CRPC6 white and the colour difference is already large; every solid after that carries this paper’s offset. The ink can be right and the report still all red.
If the customer named a data set, use that set. If none was named and you still have to match a digital proof, first confirm which CRPC the proof simulates, then decide whether the press chases absolute paper white or colour after the white difference is taken out.
How to choose
| Paper white | What the proof simulates | The press |
|---|---|---|
| Near L* 95, a* 1, b* −4 | CRPC6 | May aim at CRPC6 |
| Clearly yellower or darker | Still CRPC6 | Do not chase paper white; confirm relative comparison with the customer |
| Customer gave another data set | Matches that set | Use that set; drop the CRPC number |
Write it on the record
- Write paper white Lab* and the measurement condition.
- Write which CRPC you used, or that you used none.
- If paper white is out and the ink film is not, do not merge them into one ink fail.
