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SharonH
05-14-2009, 11:23 AM
Questions about Calibration Targets

Question 1.
It seems that some competitive Calibration/Profiling solution allow the user to print several measurement pages which the application will scan and from those measurement pages create some kind of average measurement value which will then be used for calibration. The Fiery calibrator only takes one measurement and compares that measurement with the target in order to create a correction curve. Some argue that average measurement approach is superior because it will flatten all the variations which can occur from measurement page to measurement page and the resulting calibration is “much better”. Are they right? And if not how would you explain or show to them that how the Fiery Calibrator is doing the calibration is as good or better?

Answer 1.
Overall an average solution is more work, but is it more realistic? Does and end user really see a difference between the two methods? If not, was it worth more effort? The real solution is making the printers more stable. Will this calibration “flatten all the variations”? YES for the RIP targeted color in calibration, but NO for the actual printed documents: color will continue to vary print to print

Question 2.
In the Color Profiler Suite you can let the software create a new calibration target which ideally will give you the best possible print quality. However this calibration target (and the profile) are based on a certain condition (I’m mainly referring to the engine) so if a technician would come in the next and play around with the engine settings to for example add more magenta, reduce cyan, etc. wouldn’t my calibration target then be useless? The same goes if I want to use that profile on another engine with the same media. So somebody could say using that option doesn’t make sense at all because you will have that quality only once in your lifetime and the next time you will have to create a new profile which will have a new calibration target. Is that point of view correct?

Answer 2.
This is correct, although the scenario of “a technician would come in the next and play around with the engine settings” is bad, no matter the RIP, no matter the calibration target! Profiler optimized or not! It is better to create an optimized calibration target, to ensure that you are exploiting the entire gamut from your printer. We recommend that you profile a state that you feel will be reproducible: avoid profiling a broken printer or a “super exceptionally tuned” printer. You may, but if you do, in both cases, you will have to re-profile after a “normal” service! If you had a calibration target artificially lowered, you were sadly not letting the printer gives all the colors it can produce. What I have always recommended to my customers: do not sign the papers concluding a service call until you have made a calibration in presence of the technician. If the printer is significantly under-delivering or over-delivering, it is Ok to ask the technician to touch-up. The printer DMax should be same or slightly over the profile expected DMax. You do not need a verify calibration for that.