GRACoL 7 - spectro with UV at end of name

disbellj · #1 (**permalink**) 12-21-2009, 01:49 PM

Hello all,

Hoping to have feedback from G7 Experts.

I have not studied GRACoL in a couple years, but last time I did, I had entered a proof from our proofing system into IPA Proofing RoundUp. The proof did not fall within tolerances. I believe it was because of the UV filter on my DTP41BUV spectro I had to use with DuPont CromaPro XP software that the proof failed compliance.

Well, I have been shipped a proofing system, etc. from Kodak as a way to get the company I work for to stay with their plates, etc. that Kodak sells us. They knew we were looking and trying alternatives, and so they gave us this stuff to help us get set up to GRACoL 7.

Thing is: The Eye-One Pro on the P.O. says UV at the end, which means to me that this Eye-One Pro has UV filtration - the same thing that kept my proofs from being in tolerance a couple years ago.

So I have a question for the G7 Experts:
Do I want an Eye-One Pro that says UV on it? Will I be able to get to the GRACoL 7 specification of the international standard? And if so, will I be able to scan a light color and match it if asked to? From my experience, the answers are no across the board. But since I haven't studied in a couple years this subject, I'd like others letting me know if the vendors are still screwing me while telling me if they are helping me.

Thank you.

Don

mglouis · #2 (**permalink**) 12-21-2009, 02:01 PM

Don,

They are screwing with you but hopefully out of ignorance only.

That the instrument is uv cut invalidates its use for printing to standards unless by chance your stocks have absolutely zero brighteners in them. The data in ISO12647-2 and subsequently in the G7 how-to are based on non-filtered data.

This does not mean your results might not be good, but you would have no way of knowing unless referenced against an unfiltered instrument.

Matt Louis

stargate · #3 (**permalink**) 12-21-2009, 02:32 PM

Well, I am using always UV filter in my spectro (iSis) for my proofing with my gmg system. My proofs always pass Gracol when verified with NON UV i1. The trick is to use paper that white point matches Gracol specs. I am using iSis in UV mode because it is faster and I don't use UV in my paper.

disbellj · #4 (**permalink**) 12-21-2009, 02:40 PM

Well, mgloius' reply is more inline with what I remember.

But from two answers, I get conflicting information on to use or not use. How nice it is to work in an industry where even a simple question concerning STANDARDS can have two different answers, and vendors seem to not know what standards use (UV filtration or no UV filtration), so they use whatever they want to. Nice.

Also, since I also need to match colors from previously printed pieces sometimes (that we didn't print), then if I use a spectro with UV to get Lab values, I will get different appearance than if Lab values obtained from spectro not using UV.

Only one will give me the correct reproduction of the light color. Which one is it?

Regards,

Don

mglouis · #5 (**permalink**) 12-21-2009, 02:44 PM

You can verify your results with the i1Pro, which is great. By using a different instrument for calibration and profiling than for verifying, your deltas are higher than they would be had you used the same instrument for all. The reason proofing tolerances are higher for production than for proofer certification is because of all the various instruments in the field.

disbellj · #6 (**permalink**) 12-21-2009, 03:03 PM

mglouis,

First you said:
"This does not mean your results might not be good, but you would have no way of knowing unless referenced against an unfiltered instrument."

Then said:
"You can verify your results with the i1Pro, which is great."

So I assume the first post was talking about UV filtration, and the second post refers to an Eye-One Pro with no UV filter (being used to verify or as "reference")?

Regards,

Don

Quote:

Originally Posted by mglouis

You can verify your results with the i1Pro, which is great. By using a different instrument for calibration and profiling than for verifying, your deltas are higher than they would be had you used the same instrument for all. The reason proofing tolerances are higher for production than for proofer certification is because of all the various instruments in the field.

mglouis · #7 (**permalink**) 12-21-2009, 03:17 PM

Don,

Yes, you understand me correctly.

UV-cut measurements might get you into compliance in reference to the unfiltered readings from which printing standards are based upon (e.g. Gracol characterization data), but the only way to know would be to verify the work performed via the uvcut instrument, using an unfiltered instrument for verification. Using an unfiltered spectrophotometer in the first place is simpler.

Matt

disbellj · #8 (**permalink**) 12-21-2009, 03:30 PM

Matt,

Thank you. I have sent your responses to my boss. They have a tendency to not understand what I say, or believe I don't know what I'm talking about I guess, and usually take what the vendor says (or anybody wanting to "help" us) over their own employees (when we're the ones that work with this stuff everyday, while the vendor just wants to sell you something and doesn't care about this like we do. For instance, one time I had to sit and listen to someone for two hours telling my boss he could help us, while I sat there listening. After a couple hours, and this person hadn't even looked at the press sheet to proof match, I got frustrated. My supervisor could tell, so he went out to the press, got a proof and press sheet, come in and laid it on the table, and needless to say the meeting was over in less than 5 minutes after that - after this person who was gonna help us so much realized we didn't have a problem).

Regards,

Don

Quote:

Originally Posted by mglouis

Don,

Yes, you understand me correctly.

UV-cut measurements might get you into compliance in reference to the unfiltered readings from which printing standards are based upon (e.g. Gracol characterization data), but the only way to know would be to verify the work performed via the uvcut instrument, using an unfiltered instrument for verification. Using an unfiltered spectrophotometer in the first place is simpler.

Matt

stargate · #9 (**permalink**) 12-21-2009, 04:56 PM

Sorry for the confusion. Let's clear this' If the i1 with your Kodak is the only spectro you have ask for non UV i1. I use iSis with UV on but I verify ALWAYS with i1 non UV.

disbellj · #10 (**permalink**) 12-21-2009, 05:30 PM

stargate,

Thank you for the clarification. I would say that puts the votes for NOT having a UV filter at 2 - against 0 if I only have one choice, and NOT to accept Eye-One Pro with UV filter if the boss will listen.

Thank you both. All replies are welcome.

If I sound snotty, it's just that I don't like confusion, and figured after a couple years away, all this would be figured out, and I wouldn't even be having to ask these questions because of a vendor STILL giving the wrong equipment (note: we don't use UV in our plant), especially since GRACoL 7 is published, and if I'm correct, says nothing about UV, and I can't find UV mentioned on gracol.org or IDEAliance website.

Regards,

Don

Quote:

Originally Posted by stargate

Sorry for the confusion. Let's clear this' If the i1 with your Kodak is the only spectro you have ask for non UV i1. I use iSis with UV on but I verify ALWAYS with i1 non UV.