Proofing

[mstewart]

Does anyone have a good definition of what a proof actually is. Example: "A proof is a simulation of what a printing press should produce ......." or something similar.

 

[Schnitzel]

There are several types of proof, I'm guessing you're referring to a color proof. Heidelberg's Handbook of Print Media defines a color proof as a "color-reliable/color-true reproduction of the contents of the file intended for printing".

 

[mastegman]

ISO 12647-7:2013 Proofing processes working directly from digital data' provides the following description: "The purpose of a proof print is to simulate the visual characteristics of the finished production print product as closely as possible." It includes the specifications and tolerances for proofs that are 'colour accurate' are is quite strict.

ISO 12647-8: Validation print processes working directly from digital data' describes a validation proof as a "print produced directly from digital data early in the production chain meeting the requirements of this part of ISO 12647 representative of the concept for the final product" and adds that " a validation proof can have reduced accuracy compared to contract proof". I would add particularly in relation to colour.

In my experience this has been referred to in the past as a 'positional'. In other words, it showed the layout, folds, trims, bleed, typography etc. but was not intended for colour accuracy and might be printed on various, light weight, substrates and not even at same size. It is an intermediate stage proof.

ISO 12647-7 defines a 'contract' proof. ISO 12647-8 does not. In both cases you might infer that they are 'proof' of intended outcome for a printed product although I am not aware of the origin of the term.

The ISO Online Browsing Platform (OBP) also provides two (2) definitions for proofing:

1. "printing process used to simulate final image reproduction by means of on-press or off-press methods using photochemical, electrostatic or other technologies" and

2. "<digital> process used to simulate final image reproduction using ink jet, thermal transfer, electrostatic as well as other technologies, including " soft proofing " directly from colour monitors". See link below...

https://www.iso.org/obp/ui/#iso:std:iso:12637:-1:ed-1:v1:en

Just to be sure, "soft proofing" uses no hard copy. In other words, not printed.

Mark
Teacher/Trainer, Graphic Technologies

 

[gordo]

Personally I don't think the ISO material, although well intentioned, is very useful in actual real world production. Quoting ISO won't help you to deal with an upset customer.

So, here's a way of looking at a proof that might help you chart a path.

There are basically two kinds of proof: content and contract.

A content proof shows you the elements of a file that will be imaged but not how the elements will be imaged nor how they will appear once imaged.

“A contract proof is a color proof approved by a customer with the expectation that the colors and images can be printed as they appear on the proof.”
– GRACoL

“It is the function of a proof to provide a customer-approved guide for the production pressroom by showing what the production press should reproduce from the same input films or electronic files.”
– SWOP

A contract proof is a business contract.
It supposes that all production partners (buyer and suppliers) are competent - which is not always the case.
Must be acceptable to all stakeholders
Must represent achievable presswork
Must predict presswork results
Must be consistent
Provides fixed common reference – a “stake-in-the-ground”
Represents a target for the press operator

However, all off-press proofs compromise reproduction integrity. They may hide artifacts that will appear in print and they may introduce artifacts that won't. Because an off-press proof compromises reproduction integrity there is an implication of risk. The tolerance for deviation is a gray area and is client/job/need/supplier specific. Compromise in deviation is also a gray area and is client/job/need/supplier specific. The interpretation of deviation is a gray area and is client/job/need/supplier specific.

So, the contract proofing method balances image integrity with individual client/job/supplier risk-to-cost tolerances.

Proofs are about setting expectations and mitigating risk and liability.

 

[mastegman]

The ISO 12647 family of standards, especially 12647-2 and 7, have been very well accepted and in a relatively short time so I don't know why you don't consider them useful in the 'real' world. Quoting ISO terms and definitions has nothing to do with dealing with an upset customer That's usually a result of poor communication and/or mismanagement. Using the specifications within the standards has gone a long way toward settling any arguments as we no longer rely on subjective visual assessment but on objective measurement to support it. All of the big players in this small part of the world demand it as is the case in other markets. Printing to an ISO standard is part of the contract. That's the reality.

 

[Red_Right_Arm]

Does anyone have a good definition of what a proof actually is. Example: "A proof is a simulation of what a printing press should produce ......." or something similar.

According to FIRST guidelines, it seems like there are different proofs for different reasons. And everyone needs to be in agreement which type of proof is being used and for which purpose.

All parties involved with a project must agree on the process and terminology used to evaluate and communicate color. Specifically, every proof created throughout the workflow should be clearly labeled to communicate:
- The purpose of the proof
- The system or device on which the proof was created
- Whether the output device was profiled, and if so, which profile was used
- The suitability of the proof for judging color

Concept Proof
This proof is common in the early creative stages of the project. It is used to capture input from all partners in the supply chain during design development and is also referred to as a “collaborative proof”. This proof is not typically color profiled. Therefore, these proofs should be labeled “Not For Color”.

Color Target Proof
The color target proof is often the selected “concept proof”. It represents the ideal color intent of the designer and client, independent of the print process or the ability of an individual press to achieve that color. Some of the color in this proof may not be achieved in the final print. To avoid rework costs and unachievable expectations downstream, it is helpful, when possible, to produce this proof based on the known or expected capabilities and color gamut of the anticipated printing process(es).

Comprehensive Proof (Comp)/Mock Up
This proof is formed to the shape of the final product and should indicate whether or not it is color accurate.

Profiled Contract Proof
The profiled contact proof represents the customer’s expectation of the printed product. The profiled contract proof represents the customer’s complete content and color expectations for the final printed product and is the basis for negotiations on project performance. It illustrates how the printed image is expected to look when reproduced on press and is an important quality control tool and communication device. It is profiled using a color management system (CMS) and is prepared based on profiles provided by the specific printer or prepress provider and is produced according to FIRST specifications. The contract proof does not have to be a dot-for-dot reproduction, but it must exhibit a common visual appearance to the press or characterized reference printing condition (CRPC) dataset. Therefore, it must simulate the dot gain/TVI, color attributes, detail and contrast of the printed image. It must also contain a control target that is processed and imaged as part of the proof, which will be used to verify accuracy and consistency throughout the design, proofing and printing process. The control target must contain specific screen values, which should be determined with the printer, for any colors printing dots, including vignettes. Although most digital proofing devices may not reproduce a conventional dot pattern, the tone scales should be measured using a densitometer (or spectrodensitometer) in the dot area function. Each one of the tone scales must equal the weight (dot area) identified by the press profile. Before a contract proof can be accurately used, the entire reproduction system must be characterized so that the proofing system is calibrated to match the printed result. Afterward, both press and proofing systems must be maintained for consistency and repeatability.

Soft Proof
This proof is viewed on a color-calibrated monitor. The soft proofing method can be used at any stage from concept proof to contract proof, depending on how well the system is calibrated. To use the soft proofing method, each party must have a color consistent monitor and a color management system (CMS).

 

[gordo]

The ISO 12647 family of standards, especially 12647-2 and 7, have been very well accepted and in a relatively short time so I don't know why you don't consider them useful in the 'real' world. Quoting ISO terms and definitions has nothing to do with dealing with an upset customer That's usually a result of poor communication and/or mismanagement. Using the specifications within the standards has gone a long way toward settling any arguments as we no longer rely on subjective visual assessment but on objective measurement to support it. All of the big players in this small part of the world demand it as is the case in other markets. Printing to an ISO standard is part of the contract. That's the reality.

Your ISO knowledge didn't appear to enable you to actually answer the OP's question. Red_Right_Arm gave a comprehensive answer that also gave a context to what a proof is. Which, IMHO, is the right place to start describing what a proof is. Actual specifications and standards and specifications are a separate discussion as they are meaningless without that context. And that is just one issue I have with ISO - how the specifications/standards are communicated.

 

[Malcolm Mackenzie]

An often overlooked aspect of viewing a proof is the lighting. This is especially important now with OBAs and M1.
A "Proof" on it's own is just a piece of paper with some ink on it.

 

[dabob]

IMHO . . . if the press sheet doesn't match the proof . . . the next words you might hear are . . . LUCY you got some splaining to do . . .

 

[michaelejahn]

All of the big players in this small part of the world demand it as is the case in other markets. Printing to an ISO standard is part of the contract. That's the reality.

I suppose that might be true, but that is a massive leap in assuming the OP works with contracts. My guess ISO is inknown or even cared about with a printer that has less than 1 million in sales or that type of printers customers !!!

http://www.embassygraphics.com/

I "think" that is where the OP is working.

Gordo / Red_Right_Arm are spot on - ISO specs are probably meaningless in this context. There is no "contract" - nor much more than a online soft proof ( if we can even call it that ) with many of the online print service providers...

VistaPrint,com
Mimeo.com
lulu.com
Moo.com

And who knows what lighting conditions are used at the "customer" site ( normally, some cubical near a window ! )

"Proofs are about setting expectations and mitigating risk and liability." - that is it ! CYA for MOST printers.