Dan Margulis Applied Color Theory

Highlight Variation in Proofs

   Date: Wed, 04 Feb 2004 16:29:11 -0000
   From: "william_fahl"
Subject: Matchprint Highlight Variation?

I have a printer/retoucher that is telling me that a subtle shift in color in the highlights, from one proof to another, is common in analog Matchprints. I have never heard this before and this seems a little strange considering the known quality and repeatability of Matchprint proofs. The highlight area in question consists of approximately 1-C 4-M 6-Y 0-K. The shift tends to go more yellow. It is small, but noticeable. Is this process related? Or am I viewing an acceptable deviation.

Thanks.

Bill Fahl
Studio Manager
Copper Advertising
___________________________________________________________________________

   Date: Wed, 4 Feb 2004 13:31:15 -0500
   From: Dan Remaley
Subject: RE: Matchprint Highlight Variation?

If the highlight dot on the proof is missing or smaller than they should be, it could be a processing issue. It is generally an exposure issue (under exposed). GATF makes a proof comparator (product number 7145) designed for this very purpose, to measure dot gain, gray balance and highlight values. <www.gain.net>

Dan

Dan Remaley
Process Control Mgr.
Graphic Arts Technical Foundation
___________________________________________________________________________

   Date: Wed, 4 Feb 2004 13:55:56 -0500
   From: Terry Wyse
Subject: Re: Matchprint Highlight Variation?

On Feb 4, 2004, at 11:29 AM, william_fahl wrote:

I have a printer/retoucher that is telling me that a subtle shift in
color in the highlights, from one proof to another, is common in
analog Matchprints. I have never heard this before and this seems a
little strange considering the known quality and repeatability of
Matchprint proofs. The highlight area in question consists of
approximately 1-C 4-M 6-Y 0-K. The shift tends to go more yellow. It
is small, but noticeable. Is this process related? Or am I viewing an
acceptable deviation.

Well, WHICH Matchprint proof are you talking about? The term "Matchprint" can be used (legitamitally) for anything from an analog Matchprint to a Digital Matchprint (Presstek or Creo Sopectrum digital halftone proofer) to an HP 5500 inkjet proof marketed as the a KPG5542 with a KPG Matchprint RIP on Matchprint inkjet base paper!

And, oops, I now read that you're specifically referring to ANALOG Matchprints!

Particularly for the analog and digital halftone devices, I think repeatability/reproducability under 4-5% is going to be difficult due to the lamination/removal process. It can tend to "pick off" smaller dots.

Terry
_____________________________
WyseConsul
Color Management Consulting
704.843.0858
___________________________________________________________________________

   Date: Thu, 05 Feb 2004 13:54:33 -0500
   From: Dan Margulis
Subject: Re: Matchprint Highlight Variation?

It's related more to the human visual system than it is to the process. We are exttremely sensitive to color variation in light colors. So, not just in matchprints, but in monitors, desktop printers, press sheets, even film recorders, this effect is present to some extent--if you want to pick somebody's calibration method apart, look at the highlights.

The slightly more yellow feel could be some deficiency in contacting but it's more likely to be that the substrate is slightly more blue in one case than the other. That's fairly common and would be more than enough for you to perceive a yellow shift in the highlights.

Dan Margulis
___________________________________________________________________________

   Date: Thu, 5 Feb 2004 15:09:06 -0500
   From: Terry Wyse
Subject: Re: Matchprint Highlight Variation?

On Feb 5, 2004, at 1:54 PM, Dan Margulis wrote:

The slightly more yellow feel could be some deficiency in contacting
but it's more likely to be that the substrate is slightly more blue in
one case than the other. That's fairly common and would be more than
enough for you to perceive a yellow shift in the highlights.

Is it even possible that they may be inconsistent in the Matchrpint base stock they're using? Maybe odd day proofing gets Commercial Matchprint base and even days gets Publication base?? That'd definitely alter the overall cast of the proof if you hit them on the "wrong" day!

Cheers,
Terry

_____________________________
WyseConsul
Color Management Consulting
704.843.0858
___________________________________________________________________________

   Date: Fri, 06 Feb 2004 13:23:59 -0500
   From: Dolores Kaufman
Subject: Re: Matchprint Highlight Variation?

Am I missing something here and making a fool of myself by asking this question? Oh, what the hell, it wouldn't be the first time so here goes:

Couldn't the shift toward yellow be due somewhat to the increased amount of yellow in the file: 1-C, 4-M, 6Y? It was always my understanding (from reading your book, Makeready) that a neutral highlight was in the neighborhood of 5-C, 3-M, 3-Y.

Dolores
___________________________________________________________________________

   Date: Fri, 06 Feb 2004 19:35:41 -0500
   From: Dan Margulis
Subject: Re: Matchprint Highlight Variation?

Dolores writes,

Couldn't the shift toward yellow be due somewhat to the increased amount of
yellow in the file: 1-C, 4-M, 6Y? It was always my understanding (from
reading your book, Makeready) that a neutral highlight was in the
neighborhood of 5-C, 3-M, 3-Y.

That's true, and anyone whose highlights are 1c4m6y will have warmish yellow highlights.

As I understood the question, though, he was asking why Matchprint #1 had yellower highlights than Matchprint #2 made from the same file. For that specific question, it doesn't matter whether the highlight is neutral in the first place.

Dan Margulis
___________________________________________________________________________

   Date: Fri, 6 Feb 2004 21:38:53 -0700
   From: Chris Murphy
Subject: Re: Matchprint Highlight Variation?

On Feb 4, 2004, at 11:29 AM, william_fahl wrote:

I have a printer/retoucher that is telling me that a subtle shift in
color in the highlights, from one proof to another, is common in
analog Matchprints. I have never heard this before and this seems a
little strange considering the known quality and repeatability of
Matchprint proofs. The highlight area in question consists of
approximately 1-C 4-M 6-Y 0-K. The shift tends to go more yellow. It
is small, but noticeable. Is this process related? Or am I viewing an
acceptable deviation.

As Terry Wyse asks, the first question is what is the exact Matchprint process being used? The term analog Matchprint implies the multistep laminate based proofing system compromise of a particular base and then a laminate exposed with film, for each of the four channels.

While it's possible there is some laminate variation, my past experience with this process is that the materials are consistent within the same batch. It's possible there is a batch to batch variation and that's what you've seen.

But if these are proofs being prepared within hours or days of each other, what I'd sooner expect is that the variation is coming from a failure to stop the exposure of the laminate at the proper time, consistently. Each laminate color will have a different exposure time and is based on a number of variables. If they sometime stop on time and sometimes stop 5 seconds later, or sometimes 10 seconds later, then that might explain the variation you are seeing. Although it doesn't explain why the shift would be more toward yellow. I'd expect inconsistent exposure of laminates to cause a shift in whatever laminate was inconsistently exposed...

Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
___________________________________________________________________________

   Date: Sat, 7 Feb 2004 07:42:58 -0800
   From: J Walton
Subject: RE: Matchprint Highlight Variation?

Actually, come to think of it, when we used Analog Matchprint we got some significant inconsistencies when we didn't draw down long enough. As soon as we set a standard (and slightly overkill) time for the vacuum frame to vacuum, our consistency shot up as well.

J

Adobe Photoshop training classes are taught in the US by Sterling Ledet & Associates, Inc.