ICC Digital Print day
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IS&T is a cooperating society for this event.
Proposed topics for the event are listed below. Proposals for presentations which address these issues (not product-specific or marketing presentations) are welcomed. Current or recently-graduated students are particularly encouraged to present their work. There will be a prize for the best student paper, sponsored by Océ.
If you wish to present a poster paper at this event please submit a title and 500-word abstract by 24 February 2009.
Topics
Characterising digital presses Today conventional printing presses are usually calibrated using one of the sets of characterisation data from the ICC's characterisation data registry. As digital presses have started to be used for production printing these characterisation data sets have also been used as the aim for the digital press.
Since digital presses often have a significantly larger colour gamut than that of conventional printing presses it may be better to define a workflow for digital using a larger colour gamut. The problem here is determining such a colour gamut as digital presses do not use the same inks as conventional presses or even as other digital presses. Is there a better alternative workflow for digital printing that would allow the benefits of larger colour gamut to be realised?
Native tone response Is it desirable for digital presses to support a 'no colour management' mode of operation where incoming CMYK data (usually prepared with an offset printing aim) looks reasonably good? Is such a mode needed to allow reasonable quality ICC profiles to be created?
Spot colour communication In cases where documents have been defined for printing on a conventional printing press, spot colours are often included. It is now a common requirement to be able to print such documents on a digital press. In order to be able to produce a good match for these spot colours, it is usually important to communicate additional information such as the colour of the solid and intermediate tints. In cases where the spot colour is imaged over other colours it is also important to know the ink opacity. The ICC is currently working to define this additional data with a view to adding this to the ISO version of PDF. Input from experts is invited.
Printing Pantone colours on a digital press There are a number of named colour printing systems such as Pantone, Toyo and HKS. At the recent ICC Developer Conference in Portland USA an observation was made that Pantone colours printed on different digital presses do not match each other. It was suggested that the reason for this is that Pantone wants to ensure that each colour is separated from its neighbours. This is indeed a reasonable goal but in some cases users expect a close colour match. In some ways these two aims are similar to the goals of Perceptual and Colorimetric rendering. Would it make sense to introduce the idea of rendering intent for spot colours?
Separate Absolute and Relative Colorimetric tables For some applications it may be helpful to be able to define different LUTs for Relative Colorimetric and Absolute Colorimetric rendering intents. One suggestion is to add an optional table (B2A3) that would be used for Absolute Colorimetric rendering (possibly a minor spec change).
Measuring digital print colour quality What is digital print colour quality? Colour gamut, smoothness, accuracy, repeatability are all important aspects. Users would like to have some way to know what kind of quality can be achieved but is there any standard way to do this? Given the differences in colorants and marking methods between different digital printing systems, does it even make sense to try to standardize quality assessment methods? Some examples of problems that could be addressed are non-uniformity, toning, and mechanical ghosting.
Preparing documents for conventional and digital printing It is often the case that at the time a document is created the printing method has not been chosen. If documents are created with both digital and conventional printing systems in mind printing problems can be kept to a minimum. The PDF/X Plus standards defined by the Ghent PDF Workgroup provide a good basis for document exchange for conventional printing but today there is no standard for digital printing. What additional requirements are needed for such a standard? Does PDF/X provide a good basis or are there additional requirements needed for this ISO standard?
Digital print substrates The printing substrate is an important factor in the colour reproduction and there is currently an activity among the paper manufacturers to characterise paper used for conventional printing. Can this initiative be extended to include digital printing?
Colour management for multi-ink printing Does the ICC profile specification provide a sufficiently good basis for printing systems that include more than four colours of ink? Profiles can be very large – is there a need for compression?
Spectral reproduction ICC colour management is primarily concerned with colorimetric matching. While this may be satisfactory when the spectral reflectances of the colorants are well defined, a metameric match may be difficult to predict for specific illuminants when the colorant reflectances vary widely. An example is the difficulty in matching colours on media with different levels of optical brightening. What work is being done on spectral colour management and how can this be incorporated in an ICC workflow?
Printing on non-white substrates
There are many issues involved here, for example when printing on a black substrate what is the MediaWhitePoint? What is the viewer adapted to if not the MediaWhitePoint, and how should this be conveyed to the CMM? Is there anything the ICC needs to do in order to provide a good basis for printing on these kinds of substrates?