media wedge & spots on color proofs

[Dario]

Hi all!
I'm dealing with a repro house that tells me it does not print the media wedge on CMYK color proofs because it does not print them using the "standard" profile (but what standard??) but a custom profile.
Does this sound right to you?
According to Fogra:

Its colour values must correspond to the reference values of the printing conditions, as specified in the standardisation series ISO 12647, or the tolerances for the proofing process for digital data, as specified in ISO 12647-7 or ISO 12647-8 (Validation Print).

...so maybe it's right, but I'm no expert and ask: "couldn't you print the media wedge accordingly to the custom profile?"
(Also: how do I know the color proof is good if I can't measure anything?)

This repro also tells me that it cannot simulate spot colors on proof using the custom color profile, but only using the "standard" one.

Now... I am not an expert, but it seems strange to me - if you don't use the Fogra39 (or what else) you cannot measure or certify anything?

What do you guys think about all that?
Could you kindly help me to reply their claims and helping both them and me print the media wedge and spot colors in a way to have better color proofs?

 

[Magnus]

Any CMYK profile can be proofed and verified, regardless of whether it is a standard or not.

To check if a proof matches a specific CMYK profile, you need to have the ICC-profile that corresponds to it, some kind of media wedge, appropriate software and measurement device. The ICC-profile contains a table of CMYK values and their equivalent Lab values so you don't need any other target values to make the comparison.

A certified print proof must meet certain criteria, otherwise it is not valid and should not be used as a proof. The minimum requirements are (the repro house seems to fail them all):

• The proof must have a color wedge for verification and measurement
• The proof must indicate what CMYK profile (or printing standard) it is simulating
• The proof must have a time stamp

Even if the criteria above is fulfilled, for a 'repro house' to use a custom CMYK profile instead of a standard one, is a risky (or foolish) workflow. The chances of the printer reproducing the same printing condition as the proof are very low. The printer would have to spend extra time and resources to achieve a close match, and probably do several test prints.

Keep in mind that a CMYK ICC-profile is linked to a specific printing condition, which depends on the ink, TVI, paper and more. If any of these factors change, the expected result will be hard to obtain. When printing to a certain printing standard you align your current printing condition to match the standard.

 

[Magnus]

Regarding the spot colors:

To proof a spot color, you need a precise definition of the color. I assume you mean Pantone. Most professional proof RIPs have a Pantone library with Lab targets that can override the alternate color space of the spot color in the incoming file. The Lab value is converted using a full gamut printer profile. This allows you to match most of the Pantone colors using a high-end inkjet printer (such as Epson P5000 or similar). But you need to do it correctly to make it work. And you also need to print the Pantone color on the media wedge. In your case, I suspect that the repro house does not have the expertise or software to simulate Pantone colors properly.

 

[Dario]

Even if the criteria above is fulfilled, for a 'repro house' to use a custom CMYK profile instead of a standard one, is a risky (or foolish) workflow. The chances of the printer reproducing the same printing condition as the proof are very low. The printer would have to spend extra time and resources to achieve a close match, and probably do several test prints.

Sorry, I didn't mention earlier that the custom profile is the printer's own print condition profile.

I don't see a problem with printing the media wedge either, but the repro house says otherwise.
I don't know how GMG nor other proofing software works, but it seems strange to me that this option is not covered.
I know they use GMG from the fact that the mx4 file is cited in the proofs.

Maybe I should look for an official GMG manual to look in there for the function I want, to show it to the repro house.
They don't seem to want to embark on the adventure of finding a better way to work - the typical, "we've always worked this way."

 

[Magnus]

I'm also a long time GMG ColorProof user and administrator. Adding a media wedge is two clicks away in the workflow settings. And a media wedge can be added for any proofing condition.

 

[Dario]

so YOU CAN also include a media wedge that is tied to a custom profile

 

[Magnus]

so YOU CAN also include a media wedge that is tied to a custom profile

As long as that custom profile has it's own mx-profile in GMG the answer is YES. But maybe they are doing some shortcut that I'm not aware of and therefore cannot include a media wedge??

 

[Dario]

Kindly, is there a user guide online where it states what you are saying, so I could show them?

 

[Magnus]

Kindly, is there a user guide online where it states what you are saying, so I could show them?

See the screenshot from my previous answer.

Edit Workflow properties (for the specific flow) > Image Label Control Strips > Control Strips > Select the wanted strip