There are no two ways about it – colour management is a complicated area. How do designers and those working in the graphics industry ensure that the results they get are what they are expecting, when they are, variously, viewing designs on screen; as proofs (which can produced in a number of ways); and as final printed product?
To address this, in recent years much of the printing and graphic arts industry has moved to adopt a common standard for colour management, whereby colour accuracy can be measured against an externally published set of criteria. This has the enormous advantage of allowing colours being able to be verified externally – or by both printer and designer – against a known and published standard. In Europe the standard that relates to offset litho printing and which has been adopted most generally is ISO 12647-2:2004. Adoption and implementation of this standard across a workflow should help all parties achieve consistency of digital information, proofs and print throughout a project.
(Interruption: I feel the need to define some organizations that I don’t think I can avoid mentioning. Sorry – can’t see a way round it.
The ISO (International Standards Organisation) publishes standards relating to many things; company procedures, environmental practice and so on. It does not supply or endorse colour profiles, proofing systems, or individual print companies. Instead, organizations in the relevant field work with the ISO to produce data sets such as colour profiles which are incorporated into the ISO standard. In terms of colour management in Europe, this means the ECI (European Colour Initiative), which is a body to which other organizations such as FOGRA (the German Printing Industries Research Organisation) and UGRA (the Swiss equivalent) may belong. These bodies publish datasets (such as profiles) which help industry members (such as printers) achieve the standards to which they contribute. Just to keep things simple, the profiles themselves are often written to ICC (International Colour Consortium) specifications, which is why they are often called ICC profiles. Interruption over.)
Anyways, there are a number of areas where this relates to print. The first and simplest thing a printer can do is to introduce the standard into their proofing. Many designers and colour printers these days tend to work with high performance inkjet proofing devices. As a relatively closed system, it is fairly easy to calibrate these devices to meet the requirements of the standard. This will generally involve including a test strip on proofs, which can be measured, using a spectrophotometer, to assess whether or not the device is producing colour to the required tolerances. For example, if the printer is working towards the part of the ISO standard that deals with litho printing on coated materials – which is the most commonly adopted part of the standard – the proofs will include a media strip based on the FOGRA39 profile, which is included as this part of the ISO standard. Once this strip is measured, and assuming you have the relevant software, it can be assessed against the profile and either passed or failed.
If the proofs pass, and if all parties in this project have adopted the standard as their method of working, you now have something that can be independently assessed anywhere in the world as either conforming or not conforming to the ISO standard. So a designer in Italy, for example, can send digital files to a printer in the UK, and as long as both parties can produce a proof which passes the test, both parties can be confident that they are to all intents and purposes looking at the same thing.
If they are keen to take their commitment to colour accuracy further, the next stage of the process for a printer is to adopt similar measures in their printroom. This means measuring elements of printing such as ink density, trapping, grey balance, dryback, and dot gain, and then adjusting them against the targets of the standard. This process is more complex and time consuming than those involved in proofing, and the fact that there are many more variables in printing than in the closed system of an inkjet proofer – variations in paper whiteness, for example – means that the assessment of printed sheets against the ISO standard involves a larger number of tests, and is not quite the simple “pass/fail” judgment applied to proofs. It is generally accepted that a score of 80% or over against the standard on all criteria is “working to ISO 12647”. To meet and maintain these standards requires the commitment and understanding of everyone involved in the production process.
PrintHouse Corporation has produced proofs to the ISO 12647-2:2004 standard since 2007, and began working to the standard in the pressroom earlier this year.
Tom Clark is Operations Director at PrintHouse Corporation. If you have a job on which about how colour is managed, contact PrintHouse on 020 8963 0123 or email Tom Clark at firstname.lastname@example.org