As the saying goes, "one thing that is certain is change!”
All ISO standards are usually undergoing a review, update and change. The last revision of the offset print standard, 12647-2 Amd 1 was in 2007. In December 2013 12647-2:2013 was released.
Now I will not attempt to detail all the changes in this blog - there is simply not enough time or space.
So why are we calling a standard released almost two years ago new? Good question! Well whilst the standard has been around since Dec 2013 some of the parts that make up a practical implementation, such as associated ICC profiles and characterisation data sets have not been available until now. On Sept 30, 2015, the ECI (European Colour Initiative), http://www.eci.org/doku.php?id=de:downloads
, made available for free download ICC profiles for new Coated and Uncoated stocks, mainly for sheetfed offset. These specifically are PSOcoated_v3.icc and PSOuncoated_v3_FOGRA52.icc and they are usable for the new PS1 (print substrate 1), premium coated and new PS5, wood-free uncoated. Characterisation data sets, Fogra 51 and 52 are available from https://www.fogra.org/
With these two new profiles we can now use them to set up hard copy proofing systems, for soft proofing and for RGB to CMYK conversion, in PhotoShop or in your workflow. Therefore they close the loop so to speak and enable us to implement the new standard on "press”.
As with previous versions, the 12647-2:2013 enables us to ‘calibrate’ an offset press to print within the tolerances of the target values for colour (primaries, CMYK and overprints RGB and 3 colour) and TVI (tone value increase or dot gain). Grey balance is included in the standard only as ‘informative’. But a well proven definition of a grey reproduction, I think, is entirely necessary for CMYK colour balanced print reproduction.
What has changed in 12647-2:2013?
- There are now 8 ‘Print Substrates’ (PS), which replaces the previous 5 ‘Paper Types’ (PT).
The CIE L*a*b* values for the paper substrates now matches more closely papers commercially available in the market. i.e. Papers available now have more OBA’s (optical brightening agents), which makes them appear ‘brighter and whiter’.
- The CIE L*a*b* values for the primaries, CMYK, and for secondaries, RGB and 3 colour, have been revised.
- The TVI or dot gain curves have also been revised to better reflect the now almost uniform use of CtP systems. The ‘shape’ of the curves has changed with slightly higher dot gain in the highlight area and midtone. The curves for each substrate type are still called A to E, and there is now only one curve to use for all colours, CMYK. There is no longer a separate curve for the Black.
- The dE76 formula is still used for the tolerancing of the primaries, but dE2000 values are also shown to provide you a better idea of the visual colour differences. There is still no tolerances for the secondaries or overprints.
- The new M1 measurement standard is now preferred. In around 2010 a new version of spectrophotometer standards, ISO 13655:2009 was released, covering 4 measurement modes.
M0 - This is the ‘current’ or default measurement mode for most of the spectrophotometers on the market today. Most use a ‘tungsten’ type of lamp which can have problems when measuring papers with optical brightens. These tungsten lamps have an undefined UV content.
M1 - This is the NEW one! The mode should be more closely aligned to standard D50 lighting as per ISO 3664-2009. This means the measurement should more accurately reflect printed results on a paper stock with a high amount of OBA’s.
M2 - The new mode for measuring with a UV Cut filter. This would be used to measure where the paper fluoresces and you desire to eliminate this affect from affecting the data.
M3 - A new standard where surface reflections should be minimised - with a polarisation filter - often used when measuring wet printed sheets.
- Lighting should meet ISO 3664:2009 which specifies the amount of UV for the D50 specification. Viewing system and lighting manufacturers are almost all up to date with products that now meet this specification.
If you are all ready printing to ISO 12647-2 Amd 1 2007 what do you need to do to implement the new standard.
(Below is a guide, only - your specific needs or workflow make dictate another strategy...)
- Ensure you viewing conditions and lighting complies with ISO 3664:2009.
- If you do hard copy proofing - Re-calibrate or have your proofing system re-calibrated (colour managed) so that you can output a PSOcoated_v3 proof that will verify or certify to ISO 12647-7 tolerances - This may mean you have to change to a new type of proofing stock.
If your proofing system uses an in-line spectrophotometer for calibration and verification. It should be upgraded to a device that will measure M1 mode.
You may want to also re-calibrate to produce a PSOuncoated_v3_FOGRA52 proof, if required.
- Upgrade to new measurement systems that will measure with M1 mode.
- Perform press tests to adjust and calibrate your press(es) to the new target L*a*b* values and TVI curve(s).
I hope this information is helpful for you...
I did write a detailed newsletter to my customers covering the above back in January 2014. If you have worked with me before I can possibly make his available to you. Please contact me at email@example.com
Please feel free to leave constructive comments and any relevant questions you may have.
Colour & Print Consultant