Some help with ink trapping values

[Savage]

We are trying to improve our sheetfed offset printing quality.
I'm trying to figure out if our ink is trapping correctly.
Measuring with a spectrometer/densitometer i can see that the LAB values of the C+M; C+Y; M+Y and C+M+Y are right on the spot with the ISO 12647-2 specifications.
However, according to the spectrometer/densitometer manual (it's a Techkon SpectroDens), the trapping values are wrong. Using the Preucil formula, and according to the manual, for paper class 1 (gloss coated), the trapping values should be C+M>60%; M+Y>72%; C+Y>85%, but i get all the values below these numbers (C+Y for instance goes around 75%). The ISO 12647-2 doesen't specify any reference values for trapping.

So, what i wanted to know is: Should i ignore the trapping values since the LAB values are ok, should i use other reference values for trapping, should i use the values i'm getting as reference (since the lab values are ok with these trapping values)...
I'm no expert in these things, so any help would be very appreciated!
Thank you very much.

 

[turbotom1052]

Its my opinion that you can get really stuck on the technical details of things like trapping values. The numbers you speak of wind up being a moving target. Every time any one of numerous variables change you will encounter changes in these values. To try to pin down these variables would be nearly impossible in a commercial printing enviroment where your running many different types and brands of paper. Its further complicated by climatic changes, press speeds, ink water balance, and the list goes on. My feeling is that you need to find a general purpose set of inks that will perform well under all of these conditions.
My suggestion to you is to buy a well respected national brand of ink that offers good customer support. Hire the most experienced press staff your company can afford, and look to your eyes as a source of what looks good on paper. Although all the technical details are good to refer back to on occasion ive found that its easy to get bogged down with all the information thats out there.
Here is where i take my opportunity to make a case for experienced craftspeople. In our industries quest to make the printing process a managable process, there is a tendancy for upper management to think that if THEY manage all the technical details, and purchase state of the art equiptment, that they can hire a less experienced person to run these presses. Too often ive seen it come down to the eventual realization that the place to save money isnt on Pressroom personel.