Presspercent values change when ppf is loaded into the press

Hello Everyone!

I´m wondering if some experienced ppc user can help me with this, when using the Presspercent it calculates the ink profile according to the loaded pdf and shows some inkey values but when we export them as .ppf and load it to the press through CIP3 Shinohara Station the values on the console are different, has anyone experienced this?

for example take a look to the Cyan profile:



Now check what the press has adjusted from the ppf:

the numbers are different, so I wonder, is there anyway to check the values inside of the ppf? to determine if the change occurs when exporting from ppc or when is loaded into the press?

attached is the .ppf file in case somebody may want to help me

 

This is what PPC answered on this matter:

Standard CIP3 PPF files do NOT contain any ink zone or ink key information. All they have are low resolution grayscale images of separations (plates). These images are used by software like PressPerCent or CIP3 Shinohara Station to calculate ink zone coverage and ink key values for the press console. Different software tools use different curves and different algorithms to process image data = they produce different values.

In other words:

1) If you use PPF files and CIP3 Shinohara Station, you can ignore ink zone values that are shown in PressPerCent and try to adjust curves or whatever CIP3 Shinohara Station offers for ink key values adjustments.

2) If you want to see on the press console ink key values that are similar to that in PressPerCent, you should not use PPF files and CIP3 Shinohara Station. There should be other file formats that are normally used by the press console to save printed jobs (like RSH, SRI, etc).

Now what I need is a way to upload those files to the press through the serial interface, as the CIP3 station only receives .ppf, and my floppye drive doesn´t work, any ideas?

 

Hi Camilo,

I am happy to see, that you have got PPC in the meantime.
There is another way to get your CIP3 values closer to the expected console values. You can add curves in PPC for bumping up the Zone values. It is described in details in the PPC user manual.

 

Hello Martin, Yes, thank you, I finally got in contact directly with grigori from ppc.

I´ll check the curves as you and him adviced.

 

I would warn that if you have an expectation of these values being accurate right out of the gate you will be disappointed. It's been my experience that often the bean counters purchase presses and technology that sound great as advertised, but in the real world fall pretty short of expectations. CIP3 data is one of these areas. I would say that even when things become as finely tuned as possible through much trial and error, the best you will be able to hope for will be a starting point in your presses ink settings. I myself have found that CIP data is no more accurate than my manual settings of fountains via laying the plates on the console and using my internal CIP data calculator to enter ink zone settings. It should be noted that I spent decades developing these skills. You WILL be able to count on faster ink settings once you get things optimized!!! Just another example of press manufacturers trying to convince press buyers that their brand of press can be operated with someone right off of the broom.

 

thanks for your reply turbotom but I have to tell you that we´ve been able to get a very decent preink profile with the PPC and with some predefined adjusting curves on the press be able to run jobs on ISO12647 without any other manual adjustment saving a LOT of time on the makeready, all of that done of course with the pressman´s expertise as you say.

 

How long are your typical runs, and what do you consider acceptable density deviations? If your press never gets to a steady state condition when it comes to the leveling off of ink densities, and your standards are plus or minus 10 densitometer points, and your typical run is 200 sheets, then I can see finely tuned CIP data working just fine. But to think that CIP data can be so accurate as to hold the density readings on all 4 colors plus perhaps couple of pms colors to tolerances of plus or minus 3 density points over the course of a 10,000 impression run I call BS. If such a thing were possible then there would be no need for closed loop inking!!! Now admittedly Ive been retired for the last 10 years and Im sure the technology has gotten better but I still have doubts of CIP 3s ability for accuracy at the above mentioned conditions.

 

Yes you are right, Our runs are mostly under 5k that´s why fast make ready is so important, on the other side we measure LAB color directly not density according to ISO12647 standards as I told you before, so that means CMYK no PMS.
best regards.