New ISO printing standards, OBAs and papers
For the last few years the International Standards Organisation, the ISO TC130 international committee, which develops all the printing industry related standards, ISO 12647, 12646, 3664, etc, has been slowly amending these standards to reflect more accurately the types of papers in use by printers.
This rather long blog will look at the current position with the many standards involved, attempt to put them into a current perspective and finally make some recommendations on what actions should be taken in these areas.
This has specifically affected ISO 12647/2, the offset litho standard printing conditions. However many other ISO standards have had to be revised in order to deal with this problem. These include ISO 3664 for lighting and viewing conditions in the Graphic Arts and ISO 13655 for spectrophotometer measuring standards.
Since the last version of the part of ISO 12647/2 Amd 1 2007 was published in 2007 many thought that the paper types 1-5 and their paper colour did not match the papers used in the marketplace. The reason for this was thought due to the amount of optical brightening agents, OBAs, used in papers to make then appear ‘whiter’.
These are florescent so increase whiteness and brightness by absorbing ultra violet energy and then emitting it as a visible blue white. The ISO paper types did not allow for the amount of OBAs used my most paper stocks in the marketplace.
Spectrophotometers at this time saw this as blue, so read it as a high –b in the CIE Lab figures.
As an example, ISO type 1 paper, Gloss Coated specified a CIE Lab of 95, 0.00, -2.00. Most type 1 coated papers will show a figure of b -4.00 or higher when read with a white paper backing. This is due the presence of these OBAs.
The response from the ISO TC130 committee has been to revise the standards needed to address this issue. It started with a group of European paper manufactories, The Paperdam Group, which researched the papers on this area and recommend eight revised papers types.
The new Premium Coated PS1 reads CIE Lab 95, 1.00, -4.00, also when read with a white paper backing. These new paper types have been included in the new ISO 12647/2 2013 released earlier this year. More about this later, but at present there are no released colour management data sets or ICC profiles for this revision.
Around the same time as Paperdam were working on the new paper types, the ISO TC130 committee released a new version of ISO 3664, ISO 3664-2009 for lighting and viewing conditions.
It covers colour-viewing conditions for the graphic arts and photography areas, including viewing proofs, including proof viewing booths and viewing printed sheets on press consoles.
It is similar to the 2000 version in that is stipulates the use of CIE illuminate D50 lighting, 5000° Kevin colour temperature and a colour rendering index (CRI) of 90 or greater.
It also covers the intensity and evenness of the lighting, glare, so between 1200 and 2000 lux for viewing proofs and printed sheets.
The main area that has changed is that the light source must be more accurate to the D50 specification in the UV area of the spectrum. However this may result in a differing result when comparing proofs to printed sheets.
This is because most current proofing papers have no OBA’s, optical blighting agents, while as will have seen, most papers for printing do. The new specification tubes will show this ‘colour difference‘ in a way the older tubes will not! This can result in making the match between proofs and press sheets more difficult, even when the number match!
GTI and Just will supply UV filters with the new tubes if asked. This can still be compliant with the new 2009 standard, but only if all in the viewing/approval process, including clients are using these UV filters with the new lighting!
This has resulted in the D50 tube manufacturers having to make available new specification tubes matching this revised standard.
So this you have not changed your tubes for a while, or have replaced then with older versions, you will not met this revised 2009 standard. This applies to all viewing areas, proof viewing booths, on press, etc.
A new version of ISO 13655 for spectrophotometer measuring standards was released around 2010, ISO 13655-2009, which better defined the measurement standard for papers with an high OBA content. This standards defines four colour measurement modes.
M0-This is the ‘current or legacy’ measurement mode for spectrophotometers which has the issues with measuring papers with optical brightens due to its undefined UV content in the tungsten lamp used.
M1-The new mode based on D50 lighting, ISO 3664-2009 as the illuminate to accurately measure printed results on papers with high OBAs.
M2-The replacement for the current ‘UV’ instruments, know with a defined standard for use in UV free environments.
M3-The standard for the polarisation mode, used when measuring wet printed sheets.
For more technical information on these measurement standards, see the Konica Minolta web site
ISO 12647/2-2013, is the revised ISO standard printing conditions for sheet and web fed heatset-offset litho. This revision was published at the end of 2013 and is available from the ISO web site.
First, papers, this have been revised, based on the Paperdam work to better reflect the papers in current use with their high OBA (Optical Brightening Agents), so there are now 4 coated and 4 uncoated paper types in this new version, three more then the old 2004 version.
These are now called ‘Print Substrates’ (PS), replacing the ‘Paper Types’ (PT) is the 2004 version.
The CIE Lab CMYK, RGB and TVI (dot gain) figures have been amended for each new paper type, in order to reflect the way current presses and Computer to Plate systems and plates now perform.
The CIE Lab values relating to CMYK and RBG secondaries have been slightly revised were the new substrate (PS) is similar to the 2004 version. TVI curves have had a major change to reflect CtP plate making, so a higher dot gain in the highlight area.
Also for each substrate type the TVI is the same for all colours. So the black no longer has a differing dot gain curve the CMY. They are still called curves A to E, but are different then those specified in the old 2004 standard.
Colour differences are still measured and evaluated using De76, however De2000 tolerance values are also given. This will give a better appraisal of visual differences and is indicative of the move within ISO printing standards to this metric.
The new specifications for CIE Lab figures and TVI curves will result in new colour data sets and ICC profiles being needed. At present Fogra are working on a coated profile for PS1, based on a new dataset, Fogra 51 and a uncoated profile for PS5, also based on a new dataset, Fogra 52.
As this new version of the standard prefers M1 spectrophotometer readings, it allows M0 as well. It is possible that M0 and M1 versions of these profiles with be available.
Note: The new Fogra 51 and 52 based profiles, PSP coated v3 and PSO uncoated Forga 52 v3 have been released and are on the ECI web site together with some devise link profiles.
It is hoped that testing will be complete by the end of 2014. Until then there is no compelling reason to change to the using the new version of the standard. The BPIF ISO 12647 certification scheme will be changed to reflect the new version, but not until the new ICC profiles are out of beta.
This new version of 12647/2- 2013 is much, much, more then just changing to new ICC profiles and new measurement figures. This change also may need new lighting, new spectrophotometers and changing digital proofing papers to have OBA/UV content.
The changeover to this new version does have the potential to clause confusion and error if not managed correctly with the commitment and resources needed.
One of main factors as referred to above for this new version of ISO 12647/2 is to reflect the use of OBAs in papers as discussed above. With this in mind the viewing and lighting conditions standard, ISO 3664 was revised in 2009 in order to support the extra UV emissions caused by the OBA content. So this is now within the standard and the latest D50 tubes will meet this requirement.
An M1 spectrophotometer measures and allows for the UV content caused by the OBAs. So an M0 reading giving b at -4, on reading using M1 would result in a more accurate b -6.
Older spectrophotometers will not be able to read in the M1 mode; so some updating of instruments is inevitable, both to off-line handhelds and on-press online devices.
Current ‘approved’ inkjet proofing papers are often OBA free. Proofing papers for the new profiles and M1 spectrophotometer readings will need to match the OBAs in the chosen paper type as closely as possible. These new proofing papers should be available from your normal suppliers.
Then factor in the latest US GRACol 2013 profiles based on draft ISO 15339 standard and ANSI CGATS.21-2 Characterization Reference Print Conditions (CRPC) datasets which will be specified by some US based multi-nationals, then we are really living in interesting times!
This draft standard has already adopted by the USA as an ANSI CGATS standard before it has passed all the votes in the ISO TC130 committees! Indeed the USA TC130 delegates wanted this standard to replace ISO 12647 rather then update the existing parts. However many European countries voted to continue with ISO 12647 in all its parts, while ISO 15339 was still in draft. However ISO 15339 was rejected by the ISO TC130 committee on voting, as at September 2014.
ISO 15339 specified seven CRPC’s, each a CMYK colour space, with CRPC a newsprint gamut, ‘rising’ though SC, uncoated papers, lightweight coated papers to wood free coated paper, and finishing with ‘wide gamut’ CRPC 7 which is a larger reference CMYK then the widest offset litho gamut.
The profiles associated with these CRPCs are aimed at end users, order that they can choose the correct CMYK profile and colour gamut for the paper and printing process.
The CRPC 6 coated papers dataset and CMYK profile, which is the new G7 GRACol 2013 profile, replacing the 2006 version is one of the first to be implemented.
Interestingly these datasets are intended to by printing process independent, but datasets 1 to 6 are based on offset litho, and seventh reflecting the wider CMYK gamut of some wide format digital presses.
Now, as you may now be seeing, there is now beginning to be an major disconnect between the many standards involved.
The new lighting standards and tubes that adhere to it have been available from 2011. Most new presses from the major manufactories have these lights fitted
New model handheld spectrophotometers for reading M1 have been on the market for around two years. However it is uncertain if and how many near-line and online press spectrophotometers can be upgraded to this new measurement standard. This also applier to the inline spectrophotometers in inkjet wide format printers used for contract proofing. These will need to conform to M1 readings.
The new version of ISO 12647/2 2013, is as stated, a released standard, replacing the 2004 Rev One 2007 version, but of course as referred too, there are no profiles available for use at present.
So what to do? Until the new profiles are out of beta, as referred to above, not a lot. If you have time, it may be useful to test the beta profiles, look at plans to update your spectrophotometers, plan your revised colour management workflows and research the change in inkjet proofing papers.
However there will be an ‘interesting’ change over period. The existing profiles, Fogra 39/47 etc., based on M0 readings may prove difficult to proof and match on press if using tubes with the new 2009 D50 specifications or the new proofing papers with OBAs.
These changes may take years, rather then months for both the revised ISO 12647/2 and the new ISO 15339.
With the standards changing it will also be interesting to examine how images with the older CMYK profiles with print under the conditions the new standards
Will they need to be re-profiled using Device Link Profiles?
This is a whole new project and report. Watch this space.