How important is it to make use of ICC's version 4 standard instead of version 2 for building ICC profiles? Are there particular pros or cons for either RGB or CMYK workflows?
Version 2 profiles are in common use and work very well. Version 4 profiles reflect the latest ICC standards and technology, but when using them be sure that your systems and software support this latest version. RGB workflows are good, but need a greater understanding of colour management within software and systems. Given this, the RGB image and page workflow can be very efficient for designers and clients.
How important is ink presetting to reduce makeready waste? In my experience print plants do not maintain their software and systems or optimise the settings/configuration. So typically they are wasting money on every makeready!
The best printers do make good use of these systems, but some give up to easily at the beginning of the process if it does not work perfectly at first.
What about calibration of printing presses to ensure minimal makeready waste when starting up? How often should this be done and using what test plates and procedures? Also how often should ink-presetting systems (open loop) be optimised?
Calibration or process control of presses should be part of the monthly maintenance routines. A set of linear plates with process control bars, grey balance targets for the printing condition, any specialised bars for software measurement, standard images, and a 60% plus ink area coverage should be printed. From this, CMYK CIE Lab values and related densities can be mapped and new TVI compensation curves plotted. Also, at this time the ink presetting should be re-calibrated.
Our press operators measure densities, as they can affect densities directly on the press, whereas the ISO spec specifies the LAB values, which they can't affect directly. Can that work?
The CMYK inks need to be ISO 2846/1 compliant to meet the CIE Lab values in ISO 12647/2 2004 Amd1. If then presses are set up correctly, these inks, at 'normal' densities, will match the required CIE lab values. Remember ink densities do not measure colour, so if the ink colour is wrong, density will not report this error. So density should only be used as a control, after the colour of the ink has been recorded as correct.
What part will Fogra European standards play in the UKAS Accreditation?
I guess by Fogra you are referring to the Fogra/PSO (ProcessStandardOffset) accreditation. This is based on ISO 12647/2, as is the BPIF UKAS accredited ISO 12647/2 certification scheme.
With regard to accreditation, is accreditation given for the company as a whole or to a press within the organisation?
Accreditation, or certification as it should be called in the UK scheme, will be on a press-by-press basis, and on a job-by-job basis. ISO 12647/2 is a production standard, not a management system.
There is no scoring system in ISO standards, who decides the percentages? Could it be the software suppliers in conjunction with print management companies?
The BPIF certification scheme sets scoring levels and weighting, which software and press suppliers can set as 'defaults' within their systems and solutions.
To standardise colour, we would require to fingerprint the press for dot gain, so how do you fingerprint a multicolour press, as each unit in the press may have a variable dot gain?
Yes, often each printing unit will have a differing dot gain or TVI. This can be easily measured and most CTP workflows have tools to compensate, on a colour-by-colour, unit-by-unit level.
How often does a customer's screen need calibrating?
Once a month, or every 200 hours, based on which comes first. Most screen profiling software can be set to remind you.
A little off colour management, but are there any products/solution that can measure average ink levels to PAS2020 compliance? I've built Acrobat profiles but they don't measure an average per channel over a trim box size as is required.
Good, interesting and difficult question! I guess you are referring to the 'Level 1, 2 and 3' areas of ink coverage in Objective 5 of the PAS 2020 2009. There are some software products available to help with this area:
- PressPercentPro
- Phantasm, a Illustrator plug-in
- Inkcoverage, a Photoshop plug-in
However, I am unsure, at present, how this area in the standard is measured and calculated for a number of technical reasons. The coverage of paper area with ink is easy. Coverage of tints is also quite simple. However, images are a much more complex task. The ink usage of an image will depend on many factors, ICC profile, TAC, GRC levels and the image content will also affect the listed variables. And, this is before any ink optimisation software has been used by the printer.
What is the preferred colour space for retouching images?
RGB is being increasingly used, but if retouching for printing, the CMYK soft proofing option in Photoshop should be used so you know what you are going to get on paper.
What impact does choice of paper have on 12467? Does the paper have to be pre-approved to the standard?
Most coated and uncoated papers are a little too blue to match the current ISO paper whites. But in practice this has little impact on the colour appearance. Paper can be approved to the current paper types by Fogra, but the UK scheme does not require this approval, recognising that most papers are a little outside the standard. Indeed current papers, using optical brighteners, have moved faster than the standard. It is hoped the next version of the standard will resolve this area!
How important is it for the RIP engineers to talk to the actual end-users (rather than, say, relying on the distributors)?
Very, and I hope they do, but sometimes menus and controls in the colour management areas of these softwares are not intrusive and also can suffer from poor translation from the original language.
Can workflow products manage colour across different platforms as in digital, large-format and offset?
This is possible and necessary when producing a campaign using many printing processes, litho, digital, screen process etc. The small colour gamut is litho, so a CMYK ISO profile is often used as the standard colour space. This can them be emulated on the other processes using colour-managed workflows.
Missed the printweek.com colour management webcast? Replay it now by clicking on the webcast page (free registration required).
