Proofs not Matching

[Seagull]

Can someone give me some reasons why my SWOP 2009 calibrated contract proof cannot be matched on our press. My plates have the standard 5% bump on them, Litho started running standard densities C_1.4 M_1.4 Y_1 K_1.8, but to have proper dot gain densities were adjusted so that all colors measured @ 50% were about 68 to 70. Almost all the proof matched except that the shadow areas were much darker than my proof, we measured the ink Lab values against the spec sheet and found that the Black ink was out of spec somewhat, darker, so that probably did not help, are there any press related issues that could cause this or is it the ink. Anyway tomorrow we are going to finger print he press so that it is put in proper gray balance and create a profile for proofing and see if that solves the issue.
Any input would be greatly appreciated.

 

[Louis Dery]

Can someone give me some reasons why my SWOP 2009 calibrated contract proof cannot be matched on our press. My plates have the standard 5% bump on them, Litho started running standard densities C_1.4 M_1.4 Y_1 K_1.8, but to have proper dot gain densities were adjusted so that all colors measured @ 50% were about 68 to 70. Almost all the proof matched except that the shadow areas were much darker than my proof, we measured the ink Lab values against the spec sheet and found that the Black ink was out of spec somewhat, darker, so that probably did not help, are there any press related issues that could cause this or is it the ink. Anyway tomorrow we are going to finger print he press so that it is put in proper gray balance and create a profile for proofing and see if that solves the issue.
Any input would be greatly appreciated.

Hi Seagull,
What "standard" are you refering when you wrote "My plate have the standard 5% bump on them"?

Shadow area from "standard SWOP 2009" proof can be quite different from your Litho. It’s all related to which substrate, ink, ink sequence, trap, etc.
Try first to fingerprint to gray balance, while verifying is you can get shadow area close to your proof. If NOT, you won’t be able to fix the problem with curves. You will need to think if you still want to use "SWOP" as the reference for proofing OR use your custom press profile.

Louis

 

[Lukas Engqvist]

I think you will find much info and more response in the colour management. Getts hard to follow all the discussions, but that is where matching standards is more frequently discussed.

 

[tmiller_iluvprinting]

Has anybody suggested trying to calibrate your press using the G7 method? If not, it's definitely worth exploring. IDEAlliance
Best regards,
Todd

 

[JP@mwv]

I agree with some of the other posts; G7 and its gray-balance approach to color management will deliver the best results in your pressroom. More than anything, it will force your press team to maintain best practices all the time.
Always keep in mind, your goal is to optimize the print performance of your press, then adjust your digital workflow to insure that your proof represents your press output.
I assume that your contract proof is built with dots, not an ink jet representation. If it is an ink jet representation, you may be setting too high expectations for your proof match.
When you say that your press is printing "shadow areas much darker than the proof" do you mean that the color is stronger or do you mean that you're losing print contrast. We've found that a paper's ink receptivity is not uniform across the entire range of screen values. This is one of those situations where paper quality really matters. Smoother, more consistent quality sheets will deliver better results across the whole spectrum of tone values.
Finally, finger printing your press is an iterative process. Remember the law of diminishing returns. That last adjustment to improve from 90% accuracy to 95% accuracy may cost you lots of time, effort and money. Is it worth it?

 

[Lukas Engqvist]

I assume that your contract proof is built with dots, not an ink jet representation. If it is an ink jet representation, you may be setting too high expectations for your proof match.

When we moved to digital proofs from analgue proofs we found that attitude, we fought it by doing both for a period, and the digital (inkjet) proofs are colourwise superior (when calibrated and configured correctly). One needs to know that the proofs simulate the DRY print, not the wet print.

The "bump" you talk about should be done with curves to get the appropriate dot gain. To say bumping at 5% is irrelevant. (and this is done before any profiling), but as I say there is so much on this in the colour management section, would be better to have the discussion there. (even discussing prepress press hand overs, standards etc)

Also doesn't say what paper, process you are using. First decide where you want to go.
G7 isn't a bad idea.

 

[meddington]

I assume that your contract proof is built with dots, not an ink jet representation. If it is an ink jet representation, you may be setting too high expectations for your proof match.

I'm not sure what dots would have to do with it, buts some recent studies have shown that inkjet proofs clearly exceed halftone laminate proofing systems for overall color accuracy and variation from proof to proof.