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jaBlay · #1 (**permalink**) 01-17-2007, 05:48 PM

I'm having trouble to proof contone data with spot color, example C-M-Y-Reflex Blue (replaced black channel). So much different between proofing to actual printing (i'm in packaging gravure printing). I have tried to adjust opacity of spot color but still can't find best proof.
Does anybody know and can help me?

David · #2 (**permalink**) 01-18-2007, 04:40 AM

what type of proofer are you using?
inkjet?
laser printer?
Kodak Approval?

Also, what application and OS are you using?

inquiring minds want to know

clod · #3 (**permalink**) 01-18-2007, 12:08 PM

How Ironic...I'm currently knee deep in a similar issue. GMG does a greate job simulating spot colors with one caveat...if the spot channel mixes with process, all bets are off. You can dial in the spot color solids and tints (if you have colorimetric info for 1%-99% from an ink drawdown or what ever) until the delta E is negligible, but you still may have unpredictable results when the spot mix with process color. The only tool you have is the opacity percentage, which can make an improvement, but didn't go far enough for me.

How I'm currently addressing the issue is creating a multicolor target(CMYK+Spot target) printing it, creating an N-Color profile which I will then drop into GMG, utilizing an ICC workflow. Unfortunately, GMG doesn't have a proprietary solution to N-color profiling for this scenario.

Now having the acutal press print the target is the difficult part...if you can. I'm actually printing the N-Color targets on a Kodak Approval, which I think will be more accurate to the final printing in regards to the spot/process mixes, though not as accurate as an actual press. If I could go that route, I would, but it simlpy not feasable. So, there you go...not really what you wanted to hear (or what I wanted to hear either), but that's where I'm at currently.

jaBlay · #4 (**permalink**) 01-26-2007, 07:09 PM

at now, seem i have to satisfied with the answer. hope someone in gmg read this post. btw thanks clod for reply

clod · #5 (**permalink**) 01-29-2007, 11:24 AM

GMG is indeed aware of the issue, but I should point out that this isn't limited to GMG and its usually not all that bad a match, all things considered. Any proof could have a similar issue predicting how spot channels react with process if there's no N-Color profile (created from a target of CMYK+Spots). After all, the only info you providing is usually just a solid Lab value that you want to match, usually not a gradation and almost never a number of patches mixing with CMYK. The software might be great at the solids, perhaps even the gradations, but you can't predict how overprints with spot channels will look without an N-Color profile

jaBlay · #6 (**permalink**) 01-31-2007, 03:43 PM

As you told me, perhaps creating N-Color profile would be the only way. But, I already give up to realize there are thousands or more spot color + CMYK to be made as each N-Color profile. I'm in gravure press and it's very expensive to made one chart for profiling.

clod · #7 (**permalink**) 02-01-2007, 04:11 AM

If you happen to own ProfileMaker (Packaging edition) thay have in their MultiColor profiling module a feature called Generic Output Profile (GoP) that allows you to alter one of the channels to another color and recreate the profile, so theoretically, you could change your Reflex Blue to another color, along with other adjustments, such as color sequence on press, and then regenerate the profile. I'm not yet licensed for MultiColor profiling (other than Hexachrome) with ProfileMaker, so I haven't tried this feature, but it looks interesting, though its hard to say how effective this feature is.

Back to your original issue though, is the press rendering the same or close Lab values for Reflex Blue and process colors as that of your proof? For example, what's the delta E between the Solid Reflex Blue patch of the press versus your proof? Are the gradients close as well?

jaBlay · #8 (**permalink**) 08-01-2007, 05:48 PM

sorry for late late reply.....as you know that my problem turn to deadend...yesterday i have visited by our local oris sales....he said that Oris Colortuner has more accuracy proofing for contone spot...and then offer me Oris...so, how do you think...is it really Oris better than Gmg in simulating contone spot color?

LoganBlade · #9 (**permalink**) 08-01-2007, 07:15 PM

can you print to proofer as cymk and see what happens? I did one job that I swithed out the CYMK values for spot and printing to proofer as convert to cymk gave closest results to finished product

Nicolas · #10 (**permalink**) 08-02-2007, 03:56 AM

Quote:

Originally Posted by jaBlay

sorry for late late reply.....as you know that my problem turn to deadend...yesterday i have visited by our local oris sales....he said that Oris Colortuner has more accuracy proofing for contone spot...and then offer me Oris...so, how do you think...is it really Oris better than Gmg in simulating contone spot color?

"...oris sales....he said that..."
Ask him to proof his sales statement with a real result

And ask how they achieved that

Basically the only way you can do that in Oris is to use N-Color ICC profiles, AFAIK they do not have a propriaty "GCS" solution for your process+spotcolor issue.

N-Color ICC is what you can already do with your GMG system, as clod mentioned.