ICC DevCon '08

"Consider an application developer working in the consumer application domain. The application developer would like to enable the use of camera raw images in an application that:
- enables a user to compose images into documents which include vector graphics,
- provides a print-look preview on a wide-gamut LCD display,
- and then generates a print via a home printer, achieving color fidelity with the on-screen preview.

What are the operating system supports [CMM supports] and enablements for this application and how should the application developer best use them?
What are the application platform portability factors that can affect the solution?"

9.25 am Discussion of Intelligent CMM — X-Rite CMM
James Vogh, X-Rite

10.35 am Color management in Mac OS — from RAW image data to display and print
Luke Wallis, Apple

11.30 am Colour management bricks on Linux
Kai-Uwe Behrmann, Oyranos, open source CMS

ICC Conference Lunch

Afternoon session

1.30 pm Colour measurement for profile creation
Phil Green, London College of Communication

As expectations of colour reproduction quality continue to increase, the quality of the measurements used to generate ICC profiles gains deserved attention. The provisions of the revision to the ISO standard for colour measurement in the graphic arts, ISO 13655, will be discussed in detail.

The session will cover key issues in colour measurement that contribute to profile quality, including: calibration, correction methods, accuracy and uncertainty, and handling fluorescence in samples.

The design of measurement instruments will be reviewed, including light sources, geometry and sampling methods, to provide guidelines on choosing instruments for particular applications. As well as the traditional media of paper, transparencies, and displays, colour management is also required to handle other media such as non-paper substrates (e.g. plastics and metallics), projection displays and even (for photography and motion picture) original scenes. Also to be considered are techniques for improving measurement data quality, including methods of sampling, averaging, and correcting data. Finally, methods for increasing the dimensionality of colour measurement using some advanced measurement techniques, including bi-spectral and bi-directional measurement, will be reviewed.

2.15 pm Flexible colour management for graphic arts
Craig Revie, FFEI UK

An example that involves a single image being printed is often presented when discussing ICC-based colour management. Although in traditional graphic arts, workflow images are converted for print before being placed in documents, this early conversion does not provide a very flexible workflow solution. The recently published PDF/X-4 standard provides a framework whereby coloured elements including images and other graphics can be combined in a PDF document that, when prepared correctly, can be to some extent independent of the print process that will be used to print it.

This talk describes some of the colour management challenges involved in creating and printing PDF/X-4 documents, for example how elements that are 'device independent' (elements with ICC profiles) as well as elements that are 'device dependent' (blacks, greys, pure colours and spot colours) can be included on the same page and how these pages can be retargeted at the time of printing.

3.00 pm ICC profile internal mechanics
Marti Maria, HP

This tutorial is about the underlying implementation details of ICC profiles, and is intended for profile and CMM creators. Real-world problems will be addressed including: how to avoid precision loss, how to center the gray axis, how to match white on white, and how to round properly. Many interoperability problems may be avoided by taking care of these details. The talk is divided in two parts. In the first part:

Rounding (why and how to round, different rounding methods, pro/cons of each method)
Converting between domains (accuracy, how to do it in a fast way)
Fixed point (what is it, why and how to use it, fixed point arithmetic, rounding in fixed point)
Encoding of some common color spaces (RGB, CMYK, and XYZ/Lab in PCS [limits, ranges, and differences between V2 and V4 Lab encodings])

The second part will focus on LUT mechanics. V2 LUT types will be described in detail, including CLUT, and pre- and post-linearization curves. Advanced techniques for pre- and post-linearization will be discussed, with examples. V4 LUT will be discussed next, with the introduction of the new stages and some clues regarding possible uses. The new MPE type will be introduced briefly (another tutorial deals with this exclusively). The talk will end with some basics about profile qualification and which issues to avoid: continuity, smoothing, scum dot and white match.

4.00 pm Floating point color processing with ICC profiles
Max Derhak, Onyx Graphics

The new ICC floating point capability will be discussed, along with its implied Programmable CMM capabilities. Discussion of the ICC specification change to add floating point will include: capabilities in the new MPE tag type, details of the specification change and examples, and significant technical implementation details with example profiles. Guidance will be given on using a probe profile in Photoshop to evaluate whether various transforms are executed. An example of encoding spectral data in an ICC profile will be shared, along with additional usage recommendations for MPE based tags.

4.45 pm How to use the new sRGB preference v4 profile in a workflow
Ingeborg Tastl, HP

The sRGB v4 ICC preference profile, which can be downloaded from the ICC web page (www.color.org), is a replacement for commonly used sRGB v2 profiles. It is intended to be used in combination with other ICC v4 profiles. This new sRGB profile has the following advantages:

More pleasing results for most images when combined with an ICC v4 output profile using the perceptual rendering intent,
More consistently correct results among different CMMs using the ICC-absolute colorimetric rendering intent, and
Higher color accuracy using the colorimetric intent. The tutorial will discuss the differences between the new sRGB v4 profile and existing v2 sRGB profiles, and will elaborate on how to use this new profile in a number of different example workflows.

Strategies for dealing with real world scenarios in which both ICC v2 and ICC v4 profiles are present will also be provided.

5.30 pm Kodak demonstration — soft proofing color
William Li, Eastman Kodak

Kodak will provide a demonstration of a recommended color soft-proofing methodology during the evening Networking Reception and Sponsor Demonstrations session. This final talk of the day will introduce the topic and the fundamental technical hurdles to be overcome, and describe the follow-on demonstration and display session. The color soft-proofing topic is relevant to the problem statement of the morning session, which in part deals with monitor to print matching. Pursuant to that challenge, basic differences between colorimetric matching and color appearance matching will be described.

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