Onyx RIP incorrectly printing Pantone Process Black.

[KellyP12]

Forgive me for posting this concurrently to the Signs101 forums as well. I signed up just to post here. I am looking for any point in the right direction!

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Hi all,

I'm looking for some clues as to why my issue is happening. In short, I am in the beginning stages of building a new media/ICC profile for one of our printers using Onyx 12.1. After going through the lengthy process of building my first profile from scratch, I found that when I printed one of our test prints (made here in-house), Pantone Process Black was appearing as off-white.

There is a place on our test print where we gradate Pantone Process Black in 5% steps. See the attached photo... any idea what could have caused this? I am just getting my feet wet with the profile-building process, and I know its complexities make narrowing this down difficult. Any general direction would be helpful.

My only thought as to why this might happen is in reference to an obstacle I encountered early in the profile-building process. When our on-board spectro (HP DesignJet) was reading in one of the (I think) calibration swatches, it was not reading one of the 'pure white' patches as such. It kept giving me an error, but I wasn't sure how to solve it, so I accepted the readings. We use a custom coated paper that has optical brightening agents in it, and I have learned that OBAs can affect color perception if not accounting for them (M1 vs M0 spectral data, etc.). Could there possibly be something going on there which would bounce back incorrect values enough to 'overcompensate' for paper-white and mess up how the RIP is interpreting Pantone Process Black?! Just one idea I had.

Our Spot Color Replacement table is turned on and hasn't been altered in any way. The variety of other Pantones are printing relatively accurately elsewhere on our test print.

Thanks for any suggestions you have!

 

[mikestr]

Errors in profiling have broader effect than on a single color; when that color is a spot color you can be pretty sure that your problem is your input and not your output, specifically in your spot color definition or spot color processing options/settings in your software. Be sure that the target color in the job is actually in your internal libraries, spelled identically. Normally we run on some form of red flag for missing/unknown spot colors such as printing them in orange or halting job processing altogether, but you may have set inadvertently your RIP to continue the job, simply dropping out the problem color. Since other spot colors seem to be printing I'd put my money on a missing/wrong definition or naming conflict for this particular color. I should note that there is no Pantone Process Black in the current version of the Pantone Plus Coated library.

 

[KellyP12]

Thanks for the response! Someone said exactly that in my post on Signs101 as well. It just is odd that without altering the Spot Color Replacement Table in any way that Pantone Process Black would print fine on our normal profiled media but not fine on another. This will be the first thing I try when I get the chance, though. Thanks again for the insight.