Proof unmatchable

[Proofman]

We use the Epson 4900 proofer with the Esko Automation Engine 12.2 software.
We have this system because of a customers requirement to provide them with a proof to match a proof that they provide from their system which is similar. Seems odd to me, but the proof they provide is signed off for press proof matching. This snowballed to other customers that we print for, trying to match. We profiled our presses and sent them the sheets to enter for their system. We get the files and proofs from them ok'd and in turn use their file in our proofer to try to match theirs.
Rarely have i seen them match, especially if they use a different gamut system even though they have our press profile. I tried to convince the powers that be that it is impossible to match proofs in this manner. The closest way is to curve ours, but no way will we run a job to get color then wait to curve the file to match a proof. Not cost efficient. Any suggestions?, i know this is a lot of back and forth.

 

[michaelejahn]

Using a proofing standard means "this is how our press prints" - that is - you have a printing condition ( like SNAP or SWOP 3 SWOP 5 - or one of the several GRACoLs ) on a type of paper -

https://www.flickr.com/photos/17199157@N07/6063197265/

it is HOW we can communicate "this is how it will print, BECAUSE we are printing to a recognized and agreed upon specification. it is not up for debate then. when we agree how a 50% swatch of Cyan should measure, we are within a tolerance.

If YOU are the printer, you need them to understand they THEY need to make proofs that meet your tolerances.

Send your customer these links and teach them - it is like an inch or a millimeter - we have first agree to what that means, how long an inch or millimeter is, then we all strive to make it so - we can't have this guy or that guy saying 'my inch is longer / shorter.

Sorry, it is kinda important. There is no back and forth - there is ONLY FORTH.

DEER Printing Guidelines 2011 Poster-DOWNLOAD | IDEAlliance


DEER Poster Design to Print Series 2012 - Print Edition | IDEAlliance

 

[ColorGeek]

What Michael said is valid. I would add that the curve approach is not standard - for a proofing system. Most/all proofer RIP's use ICC profiles or some other proprietary 3D transform (using "profiles") to establish the match. What you really want to know is, are the customers proofs within tolerance to the color space you've provided them to match. They should run an IDEAlliance Control Strip that you can measure to confirm this - or let them do it if they have the tools and/or inclination to do so.

 

[Stephen Marsh]

Despite reading the OP a couple of times, I am none the wiser.

Can you list in a linear step by step form the process?

You provide the proof, that is under your control and you will be held to matching your proof. A client supplied “proof” is really just an unknown print, unless it can be established that it is actually a “proof”. This may be established over time with trust, or it could be done using a media wedge, colour bar, a known target and measurements compared to a specification with dE pass/fail values etc.

If you are accepting a “proof” from an outside source, then you have to have confidence that the proof is reproducible. This does not sound like the case.

As you mention Esko, are you in packaging? Do the jobs contain spot colours? Are the proofs of halftone images or panels that may be created from a mixture of spot+spot or spot+cmyk?


Stephen Marsh