Trouble color matching blues & purples - offset CMYK, G7 methodology, GRACoL 2013

[DeltaE]

Is this problem solved?
If not, we will need you to answer the questions that have been asked by everyone.

prepress labels
You are so bad!

 

[prepress labels]

We did redo the press curve after I posted this thread--sorry for the delayed response. We've been running to a standard set of ink densities, and having a better time than before. We'll keep an eye on it.

Gordo, if you're still reading this--would the Curve4 software we're using for curves give you all the info you're requesting?

 

[gordo]

We did redo the press curve after I posted this thread--sorry for the delayed response. We've been running to a standard set of ink densities, and having a better time than before. We'll keep an eye on it.

Gordo, if you're still reading this--would the Curve4 software we're using for curves give you all the info you're requesting?

Not really. This is what I asked for:
what are your SIDs measured dry?
what are your solid ink Lab values measured dry
what are your RGB % trap values?
what are your RGB trap Lab values?
have you plotted/charted your dot gains? If so can you share?
(I'll add - what are your dot gains in 10% increments for each color when printed with uncurved plates?)
are you using the same instrument to measure in prepress and pressroom?

Ideally you'd also have taken photo micrographs of the halftone dots and also confirmed that they are consistent across the sheet.

A doctor doesn't recommend medication before doing a check on your current health status. Symptoms are noted, however, they may not determine the course of medical care. In like fashion, before applying "fixes" to the press, IMHO, it's prudent to do an audit of its current condition. That can help identify where the problem actually lies and suggest a solution.

 

[roger]

prepress labels
You are so bad!

LOL. My original question to Prepress labels is in regards to differences between GRACoL 2006 and 2013. In my opinion, the differences in cyan + magenta in blues are huge and his using 2013 as the proofer target could be the sole cause of his proof to press problem.

 

[Shaare]

Maybe I misread somewhere, but let me ask you this...
Is your designer set in SWOP v2 or GRACoL 2013 in their design apps?
Is you offset press trying to match SWOP v2 (or other than GRACoL 2013)?

If your file is built with CMYK images in a software whose color space is SWOP then unless those images are tagged they'll come in to your epson and hello there welcome to gracol! At that point your colour has most likely visibly changed. The color spaces from design to proofer to press must match if any sanity is to be had.