Anatomy of Colour - III

Question: What is ISO print standards?
Answer: ISO is the International Standards Organisation.

Question: Sounds formidable. What does it do?
Answer: ISO uses committees to create and maintain standards for a huge range of manufacturing and working practises across all sorts of sectors and industries. 

Question: What is ISO 12647?
Answer: ISO 12647 is the main standard concerned with consistent printing. It’s actually a set of related standards that are widely used by printers today to ensure that their processes are within internationally recognised tolerances. 

Question: And 12647-2?
Answer: The one most commonly used is 12647-2, which defines the results for CMYK offset printing (including heatset web offset).

Question? 12647-3?
Answer: 12647-3 is for coldset newspaper web offset, 12647-4 is for gravure, 12647-5 is for screen process, 12647-6 is for flexographic packaging (flexible and card) and magazines; 12647-7 is for “Proofing processes working directly from digital data”, while 12647-8 is for “hard-copy validation print, directly from digital data”.

Question: When did ISO do all this? 
Answer: Most of these standards date back to the early 2000s, but some have been revised since, for instance 12647-2:2013, which uses the Fogra-51 (coated) and 52 (uncoated) CMYK characterisations and profiles.

Question: Right. What about 12647-7 and 12647-8?
Answer: Note that 12647-7 or -8 are not for commercial digital printing (-8 was originally devised to get around the colour limitations of CMYK digital toners in the late 2000s).

Question: An intelligent question is coming up.
Answer: Okay.

Question: Why is there no standard for digital standard
Answer: There is still no proper digital standard, mainly because every manufacturer tends to have different gamuts in their own inks or toners. 

Question: Anything that I have missed?
Answer: Related to this is ISO/PAS 15339, a proposed new standard that defined how to get consistent colour regardless of process. This would have worked for digital printing far better than 12647 but was rejected at a late stage by the European and Japanese arms of the ISO TC130 committee that’s concerned with graphic arts standards.

Question: Why so?
Answer: They felt it was essentially an ISO label slapped on the US GRACol G7 standard, which isn’t used much outside the USA.

Question: So banished? Off with its head?
Answer: Its current status is Publicly Accessible Standard (PAS), which basically means you can work with it if you want to, but it’s not an official ISO standard. 

Question: Tell me a bit about colour spaces and the Adobe Creative Cloud?
Answer: A lot of original image files today start off in the Adobe Creative Cloud programs and are set up with its colour management. Unfortunately, this is confusing, often outdated, and needs a book all to itself.

Question: You are saying this! YOU?
Answer: Don't over-react. The Adobe Creative Cloud lets you choose ‘working space’ profiles and to assign output profiles.

Question: How?
Answer: These are shown as a choice of RGB spaces (important for monitors but also for extended-gamut printing), and CMYK. 

Question: There’s a particularly lengthy confusing list of CMYK working space profiles, many of which are for US and Japanese printshops and a lot of which are obsolete.
Answer: Correct.

Question: How does one proceed?
Answer: Simple. For UK CMYK purposes you’ll want Fogra-39, which corresponds to ISO 12647-2:2004. Even the very latest Adobe versions don’t provide the Fogra-51/52 needed for ISO 12647:2013.

Question: Then?
Answer: You can download and install these from the European Colour Initiative website at www.eci.org/en/downloads.

Question: CMYK vs RGB?
Answer: Although traditionally printers would ask for colours to be supplied as CMYK, extended gamut processes or photo quality inkjets need RGB input.

Question: It works?
Answer: This preserves the original gamut until the RIP/driver stage, where the colour separation is made according to the capabilities of the actual device. 

Question: Any final words of wisdom?
Answer: In Adobe terms, if you intend to print with an extended gamut process, make sure your input files are RGB and choose one of the RGB output profiles if you don’t have a dedicated one for the actual printer.

Question: So Adobe RGB (1998) tends to be recommended as best for print?
Answer: Yes. Adobe RGB (1998) tends to be recommended as best for print. ProPhoto has the widest gamut, but input files won’t necessarily work with this so may look worse than Adobe 1998. 

Question: Thank you, brother.
Answer: Happy CMYK to you too.

Rahul Kumar, PrintWeek India