ISO vs regional standards

[Lukas Engqvist]

Is there anyone who can describe how regional and international standards are developing? Are regional standards converging internaltional ones? Are international standards overridden by regional standards? Are some standards stonger than others? What are the primary standards to recognise in the industry?

 

[Purple Cat]

Is there anyone who can describe how regional and international standards are developing? Are regional standards converging internaltional ones? Are international standards overridden by regional standards? Are some standards stonger than others? What are the primary standards to recognise in the industry?

Lukas,

I'm currently vice-chair of the Ghent PDF Workgroup (www.gwg.org) and as such I can answer your question from that perspective.

The Ghent PDF Workgroup came into existence based on the demand of many regional end-user (mainly printer and publisher) trade organizations. They were all trying to develop regional standards but found that:
a) That was a lot of work
b) It didn't really provide a solution for cross-border printing.

What happened was a number of these regional organizations coming together and forming the international Ghent PDF Workgroup to develop more global specifications.

Doing that, it was decided very early on to base all work on the international PDF/X standards and to add additional restrictions to that standard as needed in different market segments. That means that any GWG compliant file is also a PDF/X compliant file. The international standard in this case is not so much overridden as it is embedded in the regional standards.

As the Ghent PDF Workgroup develops new specifications, two things happen:
1) As new versions of PDF/X are developed, the GWG specifications start to look at those. New versions of the GWG specifications will be based on the latest versions of the PDF/X standards, once it makes sense.
2) The regional standard organizations either just advise their members to use the GWG specifications or they derive local variants (under their own regional name or introducing small regional extras).

There is much more information on the website of the GWG, or please just ask.

Kind regards,
David.

 

[Wilco de Groot]

ISO vs. regional

ISO vs. regional

Hi Lucas,
As convener and expert in several ISO TC's and member of several other local, branche and industry TC's and WGs I think I can give you some background information.
There are basically four types of standards:
1
Company internal standards: most important to proof quality, performance specific for the own production. Can be adapted to your own production and is an absolute requirement for good quality. Not so useful for communication to others. Free to use, free to change.
2
Branche standards (e.g. FEFCO for corrugated board, TAPPI for paper, FINAT for labels etc): important within the branche, agreed upon by the generally the total chain of the branche. As these are developed by real experts these are often a starting point for ISO or CEN standards. Good for communication within the branche, sometimes not so easy to get outside the branche. Often other interest than only the branche interests are not considered. Sometimes these standards are obligatory in force by agreements within branche organisations.
3
Local standards (DIN, BSI, SIS etc.) can be adopted international standards (DIN-ISO, SIS-ISO etc) or are standards developed in a country or region for the specific situation in that area. Sometimes for market protective reasons. Local language only, so often not so useful for international communication. Often these standards are obligatory prescribed in national legislation e.g. w.r.t. safety, health, environment.
4
Internation standards (ISO, CEN) are there mainly to support international trade and prevent trade barriers. That implies that all involved countries have their say in the contents of the standard and the result is generally a very weak compromise compared to the strict and strong standards developed in the branche or in a region. Result: Everyone satisfied, nobdy happy.

Principally everyone is free to use a standard or not, and if he wants to use one he can choose the one best fitting to his purpose. Some standards are in force by local laws. Only in case of a dispute you are stronger in court if you can proof that you worked according to some generally agreed standard than if you just claim you did you best.

Wilco de Groot ([email protected])

 

[Lukas Engqvist]

Thank you. for your answer.
We are working on a converging road. We choose to make our internal standards the national standards, which in the case of 12647 is the same as the ISO. We find that the ECI interpretation has strong foothold and as it is also converging with the FOGRA 39 for coated paper, this is whar we consider to be our target.
What I was hoping to find out was the status of other international starndards? Are FOGRA and ECI and SWOP and Gracol etc also converging when it comes to TVI and Colour primaries/secondaries?

 

[rich apollo]

Lukas,

GRACoL2006 (or G7) is based on FOGRA39. Both of these are interpretations of ISO 12647-2 (on #1 grade gloss paper). There is a discrepency in the color of the blues, and something like a 3% difference in the quarter-tones.

Neither GRACoL nor SWOP will list specific TVI. In G7 methodology it's generally accepted that the TVI and SID will change depending on the paper, ink, press combination. Gray balance and NPDC are given primacy. TVI and SID are only relevant to monitor stability. If they suddenly change, then something has gone awry.

Seems like FOGRA and IFRA have done all of ECI's press testing work, so I don't think they could be really considered different.

There has still been A LOT of resistance to unification. Folks just can't seem to agree on the order of importance of the metrics. Ask two people which is more important, gray balance or TVI; and you're liable to start a brawl.

 

[Lukas Engqvist]

I thought both are. The TVI and the Gray balance.
The most common problem with acheiving the TVI is that it is not only the maximum but the shape that is important. If the TVI curve has the wrong shape the gray balance will vary in light medium and dark gray… this is why it is important to publish a full TVI target curve. The grey balance should be so that a CMY mixture should remain neutral even when changing the %, ie ratio of C:M:Y should be constant, this will not happen if the shape of the TVI curves is not correct.
This is difficult and so a target TVI would be very usefull. Shape of curve more important than the value, but value is important too.

 

[rich apollo]

Lukas,
You may have just taken the greatest stride toward unification since the falling of the Berlin Wall.

 

[cosmo]

Gray balance is only acheived through correct TVI per ink, I dont think ISO can really set a rule for this, especiallly with the many different papers we all use, this is were slight density variations from a good press man can make a difference, you can chase 1-2% tiv increases all day on your plates, and never get a perfect gray, but ive seen good press operators get it nearly perfect with .2 .5 density ink settings.

 

[meddington]

I think there have been some strides recently in the effort to reduce the diffrences between Gracolcoated2006 and FOGRA39, though outside of official standards currently(discussed at PAB meeting at Drupa). one of the big points for me in regards to print standards has always been applicability toward other processes, where tvi, imo, has less relevance as a metric defining a visual result. Particularly important as offset loses market share to Flexo and digital. Hopefully it'll get sorted out before inkjet takes over the world.

 

[Lukas Engqvist]

ISO has a problem of having to compromise where as a standard would greatly benifit from being narrow.
Cosmo even though the density will vary the shape of the TVI curve is more important than the space allocated in defining the standard. Much has been said on the TVI max%, but the shape I have found is more important than the 1-2%. A wrong shape of the TVI curve will mean that neutrals will vary from shadows to highlights (much like a chaep visually calibrated monitor).
The TVI values need in our sweep measured control strip I ignore, as it has one reading per colour. The actual value has less importance, but it needed to create the TVI curve.

Meddington, when you are talking metric defining visual results, do you mean Lab? never heard the term metric applied to colour.

 

[meddington]

>when you are talking metric defining visual results, do you mean Lab? never heard the term metric applied to colour.

I'm referring to any system of measurement. In the case of print metrics, we're talking TVI, density, Lab gray balance, NPDC, ect. I feel that TVI has less relevance in defining a cross-process visual result. G7's metrics of NPDC, gray balance, as well of solid primaries and secondaries makes for a more process agnostic sepcification. As far as standards benefitting from being narrow, I think the standard benefits the entire industry more as process agnostic, while methodologies for achieving it benefit from being narrow.

 

[Lukas Engqvist]

I think we agree only I'm coming from the practical "methodology" side. NPDC is what we use to measure a TVI curve. My point was that the SHAPE of the TVI curve is key to maintaining the grey balance at all tones. Standards and methodology need to live in harmony. The standard needs to be clear about how it is translated to practical working knowledge. A loose standard and different regional interpretations of the standard may lead to a diversity giving an illusion of the standards absence.
In the press, during print run we are relying on NPDC values for process control.

 

[meddington]

NPDC is what we use to measure a TVI curve.

We might agree completely, but I'm still a bit unclear on the above. You're saying that NPDC is the method you use to confirm a tonal response for your output device, correct? Or are you actually calculating TVI (dot gain using the Murray-Davies equation) from patches off the NPDC?

My point was that the SHAPE of the TVI curve is key to maintaining the grey balance at all tones.

This is true, but TVI itself is a bit ambiguous in this regard.. Different processes, or even the same process with disimilar consumables or screening, could require disimlar TVI curves (possibly out of tolerance to ISO 12647-2 for example) to achieve the same NPDC. TVI is surely useful as a process control metric once other metrics have been confirmed, but IMO, less useful as a defined target. ISO 12647-2 afterall does currently have six defined TVI curves.

And as for regional interpretations, the choice of the curves to follow is dependent on the "legacy insustrial practice" of the geographical area, which may be positive acting plates (curve A) or negative acting plates (curve C), a difference of 6% between the two. Add the +/- 4% tolerance on top of that and I could give you a press sheet with midtone TVI anywhere from 10% to 24% dot gain and still claim to be within ISO 12647-2 definitions...ouch.