Alois could you snip the part you are refering to, the link does not work. From what we have found there is alot of problems that printers/pressmen would blame on prepress that are nothing to do with prepress. That press instantly go as a reflex to blame prepress is sad. We find mechanical, and chemical stuff occurs at the press and even with paper, much more so that the plate. We did not have a measuring device that was able to read the contrast on the Azura plate, and did calibration on paper, skipping the plate linearisation.
We have found on odd jobs that one colour is out, but a one colour cast cannot be from a non linear plate.
Tha Azura plate does not have chemicals that are dependant on chemistry freshness/dosage or temperature to develop them. This makes the plate stable.
According to practice of certification there should be a verification of plate, this to eliminate that the plate instability is causing the problem.
Now letts go to science as a whole, if an assumed consant proves to be consistent. And in assuming the constants constant helps you localise and correct errors in other parts of the work flow is that constant not proof enough?
In relying on ANY measuring device you have to assume something is consistent, so the logic is not new.
Anyone who uses a ruler is assuming it is a constant, without proving it.
We have found larger variation in measuring equipment that in the plate itself, and it would therefore be to introduce error to fine tune to measurements in such circumstances. We do however at regular intervals, or as we see the need reevaluate our linearisation curves. We deliver printed material, and the dot on the plate is of no consequence. What is important is that prepress and press can keep a consistent Density, trapping, grey balance and TVI as specified by the ISO standard. Call me a fool if you will, but the greater folly is securing each step and loosing the whole due to extrapolated imperfections.