Achieving accurate proofs question

[gordo]

Do you proof for the effect of different substrates on presswork (e.g. set your proofer to accurately show the effect of your presswork on uncoated book stock, or for different paper colors (e.g. yellow/white or blue/white)?

If there was a service that provided you with profiles for your proofer that reflected your specific presswork on different substrates without the need for dedicated press tests - is that something you would subscribe to?

Any thoughts appreciated.

 

[Bret Hesler]

Yes, I use a matte inkjet stock for uncoated proofs, simulating everything from bright white to cream colored papers, and a satin inkjet paper for coated papers, with different simulations matching the colors of several common papers we use.

I would not use a service to handle this, as I do all of the color management for my company, but it could be beneficial for companies that do not have in-house color management staff.

 

[NathanD]

Yes, I use a matte inkjet stock for uncoated proofs, simulating everything from bright white to cream colored papers, and a satin inkjet paper for coated papers, with different simulations matching the colors of several common papers we use.

I would not use a service to handle this, as I do all of the color management for my company, but it could be beneficial for companies that do not have in-house color management staff.

Bret, are you simulating each of the paper types with a custom press profile or are you using industry standard profiles?

 

[Mike1512]

Bret, How would you create different simulations to match common paper that you use. I would assume that you create a custom ICC profile to do that or you use some sort of white point calculator to simulate the affect of different substrates. I would greatly appreciate if you can explain with more details.

Thanks
Mike

 

[Bret Hesler]

Yes, custom press profiles. The presses are G7 curved and run to Gracol solid aimpoints, so it is very close to the official profile. I just noticed there were certain colors, usually fleshtones, that were consistently off from standard Gracol proofs, and the combination of matching the whitepoint to our house stock, and profiling our ink, paper, screening combination reduced our color issues noticeably. The uncoated profile is a bit off from the Gracol uncoated. We run some UV, so we would be giving up quite a bit of gamut to run to the standard uncoated profile.

Our proofing RIP is gmg, so i can swing the paper simulation a little bit by editing the white point. For bigger moves, I have used the gracol or cgats white point adaptation spreadsheets.

 

[Prepper]

Bret, how often do you find it necessary to update that profile? And how often do you change your house stock? Our pressroom uses a lot of different papers, all 100# gloss text, but from different companies just randomly and if things don't match so well they want me to adjust the curves for them. Can't get it through how important it is to keep paper supply as consistent as possible, especially since most everything we run is the same type, 100# gloss text. I would think it pointless in our case to profile for certain paper as we never know from job to job what paper will be used, wouldn't you?
Thanks

 

[Bret Hesler]

We switched house stock once in the last 7 years. Occasionally, paper manufacturers will change the shade of the paper. We mostly know what paper we will be using when a job is written up. It sounds like your issue is a purchasing one, getting whatever is available and/or at the lowest price. Maybe tracking press down-time $$ due to paper variation would help sell them on standardizing the paper supply.

 

[Magnus]

We have three different simulations on two different proofing substrates. One for Fogra39 on silk coated paper (the substrate wp is according to Fogra39 so no paper simulation is needed). The other proofing paper is a matt coated paper for simulation Fogra47 (with paper simulation) and something that we call 'Fogra47 Cold Whitepoint' (no paper simulation). The matt coated paper that we use is matching the wp of our uncoated house stock that has a cooler wp then Fogra47 and has much more OBA:s. Until we switch to the new Fogra51 and Fogra52 standard, we get good result using this method. Good match between proof/print/display.

 

[David Milisock]

Ok is it me or what? I've been doing graphics since 1975, started out on R Hoe metal decorators, ran 6 color Heidelberg presses, went into management, ran a few companies then started my own. I've bought printing all over the United States, I do high end color correcting for architectural printing in Europe and I've NEVER EVER seen a proof that matched the press.

I've seen some that made it easy to sell work and some that made it tough to sell work, the Kodak Approval made it easy to sell work and make the client happy. Any of the modern ink jet proofing systems I've seen have never gotten more then a shrug and an ok from my eye.

 

[Stephen Marsh]

…and I’ve NEVER EVER seen a proof that matched the press.

There are two schools of thought, most today lean toward the idea that the press should align to the proof – rather than the proof aligning to the press.

Usually photographic work matches when a press is run to a specification that aligns to the proof, however large panels of solids and tints are of course challenging and I often don’t see a “match” there.

As you would expect, Gordo has a blog post on this:

http://the-print-guide.blogspot.com.au/2009/01/press-and-proof-alignment-strategies.html


Stephen Marsh

 

[Magnus]

I've NEVER EVER seen a proof that matched the press..

Hi David I'm interested to know your definition of the word "matches"?

We are printing accordingly to ISO 12647-2 and when we are inside the tolerances (∆E) of this standard of both print and proof we have a match. Visually the proof and the print matches. It does not look exactly the same in every aspect but it fulfill it's purpose of giving the client a good hence of what the final product will look like for a reasonable cost.

Best regards,

Magnus Sandström

 

[gordo]

One important caveat - one should never ever use the word "match" when speaking about press work and proof. The term is "align."

 

[David Milisock]

Hi David I'm interested to know your definition of the word "matches"?

We are printing accordingly to ISO 12647-2 and when we are inside the tolerances (∆E) of this standard of both print and proof we have a match. Visually the proof and the print matches. It does not look exactly the same in every aspect but it fulfill it's purpose of giving the client a good hence of what the final product will look like for a reasonable cost.

Best regards,

Magnus Sandström

Ok here's what I see, objects in the file, image A,B,C and D, vector A,B,C and D.
They all look, under controlled viewing conditions one way on the proof and another way on the printed product. Matching means they look the same way on both. The best example of that definition would be to pull TWO CONSECUTIVE PRESS SHEETS from a run, now there's a match as close as one can get. The untrained Designer hears color proof and expects to see the same on one as another. Clearly one has to inform the designer about viewing conditions and manage expectations.

THIS HAS NEVER HAPPENED, as I have said the Kodak Approval was the best I've ever seen with color.

Color proofing technology today runs the gamut from mostly awful/bad ( images render significantly different on the proof and the press sheet) to ok where the rendering differences are still IMO vastly different but not as bad, to the best I've seen where the differences are STILL PRESENT but only different in a major way.

When print dimensions allow I have digital press and ink jet proofs runs simultaneously and explain the color variations to the client.

Some vendors do have their digital device very close o their press and when dimensions allow this is how I'll proof with those vendors.

Color management has always been in the file, the computer could not operate without it, the modern processes have been both a significant improvement and IMO due to lousy marketing and improper client management a problem the industry. While color management provides significant ability to maintain file color integrity without customer service that properly manages expectations it's just BS.

 

[David Milisock]

One important caveat - one should never ever use the word "match" when speaking about press work and proof. The term is "align."

I prefer manager expectations.

 

[David Milisock]

There are two schools of thought, most today lean toward the idea that the press should align to the proof – rather than the proof aligning to the press.

Usually photographic work matches when a press is run to a specification that aligns to the proof, however large panels of solids and tints are of course challenging and I often don’t see a “match” there.

As you would expect, Gordo has a blog post on this:

http://the-print-guide.blogspot.com.au/2009/01/press-and-proof-alignment-strategies.html


Stephen Marsh

How can you align one object the press with ink set A, (4 specific hues) with another object with ink set B ( 4 to 8 different non matching hues)

IMO the best you can do is profile the press and consistently run to that standard, profile the proofer as best as possible and manage the client proofing expectations.

Moving the press around is always done by a few points but for significant moves is a poor choice.

 

[Stephen Marsh]

How can you align one object the press with ink set A, (4 specific hues) with another object with ink set B ( 4 to 8 different non matching hues)

IMO the best you can do is profile the press and consistently run to that standard, profile the proofer as best as possible and manage the client proofing expectations.

Moving the press around is always done by a few points but for significant moves is a poor choice.

David, the press is setup to specifications such as using the correct ink, and CMYK target densities are run to achieve specific primary and secondary overprint L*a*b* target values, while additionally TVI curves are also applied to target the tonality and colorimetric requirements of the specification.

The press is performing as close as possible to a specification.

Proofing is setup to the same specification.

<toungeplantedfirmlyincheek>There is a wonderful invention loosely titled “ICC colour management" that is used with proofing, this is what is used to colorimetrically simulate a CMYK analogue press condition using an inkjet with different paper and ink. Perhaps you should look into this technology.</toungeplantedfirmlyincheek>

Both the press and the proofing system are targeting the similar/same colorimetric target. The inkjet target is less variable/more stable, so this is the “fixed” target that is signed off by the printer and the print buyer. The press is then aligned (not “matched”) to the proof.

Whether the proof is setup to an industry specification or to a “house condition” is not the issue, both have been successfully performed for decades and both have the same concerns with process control and managing client expectations.


Stephen Marsh

 

[gcplau]

There are two schools of thought, most today lean toward the idea that the press should align to the proof – rather than the proof aligning to the press.

Usually photographic work matches when a press is run to a specification that aligns to the proof, however large panels of solids and tints are of course challenging and I often don’t see a “match” there.

As you would expect, Gordo has a blog post on this:

http://the-print-guide.blogspot.com.au/2009/01/press-and-proof-alignment-strategies.html


Stephen Marsh

Stephen, I agreed half of the saying because a proof, particularly the G7/PSO cert proof, is simulating a press standard, and such press standard is kind of a norm or averaged results of such press/paper. Thus, a printer's press is to upkeep the agreed ISO standard set upon.

To me, G7/PSO proof is a faster and cost effective way to show the client the visual result of a printing standard agreed upon (for e.g. ISO-12647-2 sheetfed on coated stock0:
while for a printer, they keep up all the variables and make sure they do the printed jobs according to the "expected" color behavior/outcome such as the ISO Ink, The TVI, trap, gray balance, ink tac, humidity, chemistry.....too many variable but routing to one expected result and outcome.

Maybe I"m ancient man... rarely saw people look at these two things alike.

Decades ago....you hear people say the digital proof suppose to match and simulate the "wet proof" in the old days. So, it becomes a simulator simulating another simulator.

For the same thought and logic, a digital proof is only simulating an agreed printing standard/spec/result; while a press just perform these standard/spec/result.

Proof is a simulator; Press is a Performer. ISO-12647-x is the Target.

 

[gordo]

I agree with this 100 percent. While there are many variables on an offset press, as long as everything is set up correctly and kept under control, the press work is the target. It's what the customer is actually buying and it's what ends up getting used. A proof is supposed to be something to give them an idea of what their product should look like, without having to go all the way to press to show them. IMO, too many people have that backwards and expect the presswork to match a 'simulated' proof.

A digital file is comprised of 4 colors only, and those 4 colors just happen to be the same ones used on press.

A proof is the representation of the characterization data reflected in the ICC profile that drives it.
If the press is set up to reflect the same characterization data then, both proof and presswork will align with one another.
It is unlikely that they will match one another because of the very different mechanics of how each creates color.
A proof does more than give the print buyer an idea of what the presswork should look like. A proof is a contract between print supplier and print buyer which is why most printers have their clients sign the proof before the job goes to press. The proof sets the expectations for color and content.

 

[gcplau]

A proof is the representation of the characterization data reflected in the ICC profile that drives it.
If the press is set up to reflect the same characterization data then, both proof and presswork will align with one another.
It is unlikely that they will match one another because of the very different mechanics of how each creates color.
A proof does more than give the print buyer an idea of what the presswork should look like. A proof is a contract between print supplier and print buyer which is why most printers have their clients sign the proof before the job goes to press. The proof sets the expectations for color and content.

I am kind of surprised that Gordo is still explaining the existence, role and value of a color proof....it's been here for ages.

I do not agree at all proof/press match is about different mechanics....totally not agree. The very large part between digital inkjet proof and sheetfed press for e.g. is not about mechanic....it's about the many challenges sheetfed has to deal with in order to keep the press stable from left to right, head to tail, make ready to end of press; while for digital proof like inkjet, the variable are relatively less...nowadays, proofer w/ spectra builtin can calibrate automatically in 10~15 minutes, and ready to go for a low delta-E for the full day. As for press on the other hand, it takes a lot of regular maintenance and process control to achieve reasonably good stability... but from left to right, head to tail, it's deltaE is non comparable to nowadays inkjet.

In short, IMHO, the digital proof's mechanic offer it relatively higher linearity across the full sheet when comparing to sheetfed, the add'l color gamut only benefit spot colors while good calibration can make use of the wider gamut to simulate the press CMYK color and other characteristics of TVI, trapping, wet on wet..etc.

 

[gordo]

I am kind of surprised that Gordo is still explaining the existence, role and value of a color proof....it's been here for ages.

There's an old marketing adage that states "Everyone in town knows where the church is, but every Sunday they still ring the bell."

I do not agree at all proof/press match is about different mechanics....totally not agree. The very large part between digital inkjet proof and sheetfed press for e.g. is not about mechanic....it's about the many challenges sheetfed has to deal with in order to keep the press stable from left to right, head to tail, make ready to end of press; while for digital proof like inkjet, the variable are relatively less...nowadays, proofer w/ spectra builtin can calibrate automatically in 10~15 minutes, and ready to go for a low delta-E for the full day. As for press on the other hand, it takes a lot of regular maintenance and process control to achieve reasonably good stability... but from left to right, head to tail, it's deltaE is non comparable to nowadays inkjet.

You disagree but then cite the some of mechanical issues that cause the proof and press not to "match." I don't understand.

In short, IMHO, the digital proof's mechanic offer it relatively higher linearity across the full sheet when comparing to sheetfed, the add'l color gamut only benefit spot colors while good calibration can make use of the wider gamut to simulate the press CMYK color and other characteristics of TVI, trapping, wet on wet..etc.

This has nothing to do with "linearity."