Search: for:

CHROMiX ColorNews Issue #26 - Vista's New Color Management System: WCS

SmartNote: 50022
Type: ColorNews
ColorGeek factor:

Welcome to ColorNews, a periodic update on things related to Color Management.
We strive for a periodic newsletter of high value to our customers.
Please let us know your interests so we can address these concerns in future issues.

C H R O M i X C O L O R N E W S

Issue # 26
Feb 14th, 2007 (Happy Valentine's Day)


Table of Contents


1. Shows and Events
2. CHROMiX News
3. Color Industry News
4. Vista's New Color Management System: WCS - an Article by CHROMiX President Steve Upton
5. CHROMiX Open Box items for sale
6. ColorNews Administration (feedback, subscriptions, etc.)



Feb. 27th, 2007 - Monitor Calibration and Other Cool Things To Do With A Spectrophotometer, hosted by the Seattle Chapter of the Pacific Northwest Color Management Users Group, 7:00 PM at the Adobe Campus in Seattle, WA.
Click here

Feb. 28th - March 4th, 2007, Graphics of the Americas 2007 and Xplor Conference 2007 combine once again for one of the worlds largest events of its kind. The event is held at the Miami Beach Convention Center, Florida. Xplor's vertical markets include banking/financial, insurance, service bureau, direct marketing, government, manufacturing, medical, manufacturing, utilities, and other Fortune 1000 companies. Graphics of the Americas attendees include thousands of commercial printers and graphics-oriented, creative professionals. Together, the target audience is expected to be over 22,000 CEO's, E-Doc, IT managers and executives and creative professionals from around the world.
Click here

March 1st, 2007 - Portland Chapter of the Pacific Northwest Color Management Users Group presents 'Quark v7 for Color Management' by Leith Speights from Quark. 7:00 PM at The Oregonian, Portland, OR.

March 5th, 2007, IDEAlliance Proofing Summit, Marriott Marquis Times Square, New York, NY. This is a great opportunity to review proofs complying with new "to the numbers" certification criteria (GRACoL and SWOP). Also, attendees will be able to contribute input to the new standards.

March 8th - 11th, 2007, PMA 07 International Photography Trade Show & Convention, Las Vegas, NV. This event is undoubtedly the largest show for the photography market.

March 7th - 11th, 2007, Top Management Conference, Four Seasons, Santa Barbara, CA. This is an NAPL event. Click here

March 27th - 28th, 2007, Print Outlook 07, Fairmont Hotel, Chicago, IL. Geared towards industry executives and managers in marketing, sales, finance, research, manufacturing, and operations and involved in every aspect of design, commercial printing, publishing, and converting and delivery. Dr Joe Webb and many other financial experts will be speaking about the current state of the industry and what to expect in the upcoming year and beyond.
Click here

April 25th - 27th, 2007, 'ad: tech' Conference, Moscone Center, San Francisco, CA. Learn from Ad and Marketing experts about current trends.

September 9th - 12th, 2007, GraphEXPO and Converting Expo 2007 USA, Chicago. Regarded as the USA's most comprehensive prepress, printing, converting, and digital equipment trade show and conference, it is estimated that over 40,000 industry professionals will attend this event.




CHROMiX has recently been accepted by the ICC as a Regular Member of this renowned standards organization. We look forward to participating in the ongoing development of the ICC Profile Format Specification. We'll keep you apprised of any noteworthy announcements or developments.

Maxwell, a revolutionary new color management system based on a central web-enabled color repository, is developing nicely, and we expect to launch it by the end of March. Maxwell offers device trending, color profiling, profile sharing and measurement services. Maxwell also creates color profiles for Microsoft's new Vista operating system for easy download and installation. We will offer subscription and other purchase plans, and have referral, reseller, bundling and OEM opportunities available.

We apologize for the delay in our Maxwell webinar presentation. We have set the date and time for February 28th at 10:00 am Pacific Std Time. For those who expressed interest in this webinar, you will receive an email with the date and connection information. If you haven't signed up yet, send an email to us at or give us a call at (206) 985-9844.

ColorWiki continues to evolve. Manuals for the following products are now listed: ColorThink v2, ColorThink Pro v3, IDEAlliance IDEALink Curve, Left Dakota's Link-o-later's Introduction, User's Manual, Interface, and Troubleshooting. Let us know if you would like your manual listed. We also have over 40 interesting color management related articles. We would love to have more articles. Your article can retain the copyright and we can restrict editing by general wiki users OR contribute to the body of open source articles. Check it out:

The next ColorThink Pro Webinar Training session is coming February 28th at 12pm Pacific Std Time. The WebEx class, which consists of one two-hour session and one one-hour session, is taught by Steve Upton, designer and developer of ColorThink. The first two hours cover fundamental and intermediate use, and touch on some advanced concepts. The second session, held at a later date agreed upon by class attendees, focuses on advanced concepts and questions. The class is presented in this manner to allow plenty of hands-on time with the program before the final hour of training. Interested? All you need is a current browser, and ColorThink Pro. Pricing: $349 for the Webinar class, $598 if you need an upgrade from ColorThink to ColorThink Pro and $748 if you are starting from scratch (no upgrade) for the training and the whole ColorThink Pro program. For more information or to register, call sales at 866-CHROMiX x1, or email

The ColorValet Software Client has also seen some upgrades and
refinements. Stay tuned for more improvements!


Color, Product & Industry News


Adobe will ship Mac and PC versions of Lightroom v1 on February 19, 2007. Lightroom is Adobe's professional photo management and RAW conversion software. Also on February 19th, Adobe plans to release Camera Raw v3.7. This version adds support for RAW files from the Nikon D40 and Pentax K10D. Also key, it will introduce cross-application compatibility between Lightroom and Photoshop CS2 RAW processing settings stored in a RAW photo's XMP file. For more information about Lightroom: Click here

Hewlett Packard USA launched a campaign to lure owners of other brands of wide-format inkjet printers over to one of HP's new 8-ink or 11+1-ink printer models. The program is called the HP Extreme Upgrade program and offers a rebate of between $500-$1000 (US) plus up to $500 worth of paper when a Designjet Z2100- or Z3100-series printer is purchased. For more: Click here

Author and Photographer Giorgio Trucco did an informative review of the new Epson Stylus 3800 posted at Digital Outback Photo. He highlights using the 3800 for B&W usage. Not unnoticed was his use of ColorThink for some of his evaluations. For more:
Giorgio Trucco's website

Two Electrical Computer Science engineers from South Korea have proposed a very interesting idea. Yeong-Ho Ha and Chang-Hwan Son have listed an article on the SPIE website (International Society for Optical Engineering), proposing a system for real-time color matching between cameras and mobile phones (still and motion). Check it out and ponder:
Click here

Interesting Technical Tip for Vista: (but read this issue's article for Vista warnings)
How to make a Monaco Optix XR Pro work with Microsoft Windows Vista OS

please go directly to the Luminous Landscape forums for this tip. You can find it here:


This Month's Feature Article: Vista's new Color Management System: WCS

by CHROMiX President Steve Upton

Recently Microsoft released their delayed and highly anticipated upgrade to Windows: Vista.

There is no shortage of articles analyzing Vista, its requirements, its new features, and many of the changes that will take place for the user and software developer. What I have not seen, however, is an article addressing Vista's color management system (CMS) capabilities. So here we go.

Windows Vista includes a significant upgrade to operating system-level color management. The Windows Color System (WCS) represents an departure from the ICC-based architecture that most CMSs have used for the past 10 years or so. As I often do with many of my articles, let's take a few steps back to put it all in perspective.

Windows 2000 and XP include Microsoft's CMS called Image Color Management (ICM). The Color Management Module (CMM - I hope this is the last of these acronyms) was originally written by Heidelberg and has not seen much of upgrades or bug fixes over the years. As a result of this low priority on Microsoft's list, ICM has had enough bugs and short comings few people rarely use it for color conversions. Though you can select ICM for conversions in Photoshop and other applications, few users do. Many print drivers and RIPs on Windows use CMMs licensed from Kodak and other companies. It's fair to say that those of us in the professional realm had given ICM up for dead.

Windows ICM, Apple's CMM in the Mac OS, Adobe's CMM "ACE" in their publishing applications, Kodak's CMS and most other major color processing systems have used the architecture and profile format described by the ICC. In this architecture (at least thus far) the basic components have been 'smart' profiles and a 'dumb' CMM. This is an over simplification but it captures the basic building blocks.

In the early to mid 1990's computing power was only a fraction of what it is today. Calculating color transformations took time - 5 to 20 minutes or so - and it wasn't realistic to calculate these tables real-time in production workflows. At the same time, the bleeding edge of color research lay in mapping gamuts and transforming color as smoothly and realistically as possible. By placing the color mapping function into the ICC profile, the CMM was left to perform the much simpler - and faster - job of converting image colors using simple interpolations of the profile's tables. The hard work, both in design and computation, is performed off-line when the profile is originally calculated from color measurement and reference data. Profiling software manufacturers can refine and revise their color conversion technology to bring us better and better profiles without us having to upgrade our publishing applications. Competition between profiling vendors would also drive improvement in color technology over time. All in all, a wise method to get us through the first 10 years of advancement.

But over time, shortcomings in the architecture came to light. One of its primary strengths turns out to be a weakness as well. Recall that ICC device profiles perform half the required color conversion. In a normal workflow, when an image is converted between two color spaces (say Adobe RGB and SWOP CMYK), two profiles are put to work and they hand off the image color in the Lab color space. By selecting Lab (and sometimes its cousin XYZ) as the profile connection space the ICC gave us the brilliant system where a profile only needs to know about converting between its device and Lab. Users can select profiles on the fly and the CMS knits them together to perform the conversion. Profiles can be combined in different ways to convert from device space or to device space. Profiles can be used for matching between devices or simulating one device on another. The problem is that the very calculations that map color between one device and another are performed when we don't know what the 'other' device will be. In other words, when I choose the perceptual rendering intent, the tables in my source profile and in my destination profile will both try to map color from the, typically, larger source gamut to the smaller destination gamut. As I mentioned before, this stuff is the real rocket science behind color management and yet neither profile can be aware of the size and shape of the other's gamut. This can result in sub-optimal hand-off between profiles and inaccuracies or unnecessary desaturation in color conversions.

Another example of this is black point compensation. BPC is an Adobe work-around to this same gamut-blindness. With BPC, the Adobe CMM evaluates the lightness range of each device gamut and scales between them. BPC is performed in the CMM, has been only available in the Adobe CMM, and was outside the ICC spec.

For this and other reasons, advanced users have been calling for a change in the architecture to allow for moving some of the smarts from the profile into the CMM. The ICC is evaluating several options to change the way profiles interact as well.

Windows WCS, as you might have been able to anticipate, is based on an updated architecture where the profiles are simplified and the CMM enhanced. ICM, the ICC-based engine is still playing along for the times when users supply ICC profiles for their conversions. The new features and interplay between WCS and ICM are a bit involved so let's step through it:

- WCS profiles are NOT compatible with ICC profiles. They are XML-based text files that are much simpler and do not contain gamut mapping calculations at all. Think of them as slightly processed measurement files.

- There are three different kinds of WCS profiles: device model, gamut mapping method, and appearance model. The device model profiles contain the color measurement information from the actual graphics device. The gamut mapping method profile selects which gamut mapping technique the user desires. WCS is based on CIECAM02 appearance modelling. The appearance model profile contains the parameters for CIECAM02 transforms. This is where you might specify the color temperature of the lighting used to view your print or the color and intensity of its surround.

- WCS and ICM work hand-in-hand in Vista. If all the profiles supplied in a color transformation are ICC-format, then ICM is call upon to do the processing. If one or more of the profiles is WCS-format, then WCS takes over and performs the conversions.

- If WCS is performing the conversions, any ICC profiles in the workflow are converted to WCS format prior to processing the image color data. Any gamut mapping in the ICC profile is ignored and WCS treats it as a virtual device, reconstructing the device measurements from the A2Bn tags in the ICC profile.

- Microsoft has upgraded ICM to version 3, fixed its bugs and updated it to use ICC version 4 profiles, bringing it up to date and hopefully removing any processing problems we've seen in the past. This is great news as it shows that Vista will be able to play with all the ICC profiles in the world and fit into existing color workflows. ICM is still based on the original Heidelberg code.

- Because WCS calculates the color transformation on the fly, gamut mapping should be more efficient and accurate. WCS has the information for each device's gamut and can presumably make better judgements and choices when dealing with out of gamut colors. This also means that black point compensation is automatically handled at this stage. (more on BPC below)

- WCS can also perform calculations using floating point math and allows device models to describe where to map diffuse whites and specular highlights. This and other enhancements allow for a number of new things to occur such as avoiding possible round-off errors on 16 bit devices, support for high dynamic-range devices (like the new digital projectors in movie theaters) and also extended gamuts.

- WCS can also be set to preserve the black channel through a workflow. Something for which ICC users require device link profiles at this time.

- By separating the device information from the gamut mapping and viewing data, users may be able to address specific color problems in the most appropriate area. Gamut mapping issues could be addressed separately from device measurements and viewing issues. In ICC profiles today, all the functions are combined during profile construction into one table.

- WCS can convert WCS profiles to ICC profiles. After conversion, the original WCS device profile is embedded into the ICC profile as the 'MS00' tag. In this manner WCS profiles can be embedded into image files as ICC profiles.

- WCS is only available with Windows Vista and Microsoft has stated it will not be made available to Windows XP.

- WCS was developed in conjunction with Canon.

- Microsoft has documented the daylights out of WCS so very little of it is based on 'magic sauce'. Also, many of the algorithm components are extensible or replaceable so developers can write their own plug-ins and alter device models (how the system expects devices to behave, inks to mix, paper to absorb), gamut mapping and so forth.

- Microsoft has created a useful demo image that contains an ICC profile that has a WCS profile embedded within it. The image and profiles are constructed in such a way that a Ducati motorcycle appears to be blue, green or red if the profile is entirely ignored, the ICC component is used, or the WCS component is used, respectively. It's worth a look:


So, with all these new features and capabilities are there any shortcomings? Well, yes. This is a version 1.0 product after all.

- The WCS CMM essentially has black point compensation ON at all times. In most cases this is good, but if you don't want the blacks intelligently improved - such as when you are proofing - then it means you won't be able to simulate a printing system that has lighter blacks than your inkjet or monitor.

- WCS can handle CMYK devices but at this time there is NO control over CMYK parameters such as total ink limit, black start, GCR level, etc. Laser printers are very different than inkjets which are very different than offset presses. WCS can support different device model plug ins but that is more like presets and I believe there is only one CMYK model shipping with WCS at this time.

- WCS does not support more than 4 print channels. So no Hexachrome or other n-color printing systems.

- WCS, like Windows XP, still does not load calibration curves from monitor profiles. This one deserves a little background... After you calibrate and profile your display, the profiling software saves the graphics card's calibration curves inside the monitor profile so they can be reloaded on reboot. The Mac OS has reloaded these curves automatically since OS 8 but on Windows, a third-party utility is required. This is open to conflicts as two different software packages might fight over loading curves (LUT wars). Also, selecting different display profiles in the displays control panel does not load each profile's calibration curves... cumbersome at best. This is an odd oversight as it is a simple function and one that really should be performed by the OS.

- A more serious problem, and this one is a show-stopper in my eyes, is the authorization bug. As you use Vista, you are occasionally interrupted by the OS as it confirms you have the admin-level privileges required or confirms certain actions. As a user-interface effect, Vista dims the screen slightly while offering the user a password dialog. Unfortunately, this dimming of the display clobbers the calibration curves in the graphics card and they are not replaced. So you startup Vista, your 3rd party utility loads your display calibration correctly but then 5 minutes into your session Vista requests some authentication and your calibration is gone... so you restart Vista, reloading the calibration and start out again.... It will be difficult to have confidence in a system's state of calibration.

- The WCS user interface is limited to a simple default-profile configuration panel at this time. Windows XP has a more capable utility available for color settings but it is not compatible with Vista at this time. It will find its way to Vista eventually.

- ICC device link, abstract & named color profiles are not supported in WCS. This is not too much of a shortcoming as device links are the most popular of the three and yet the on-the-fly gamut mapping and black preservation of WCS may render device links unnecessary. Then again, device links are typically used to get around CMM limitations so... These profile types are supported in ICM however.


One of the more challenging things about evaluating Vista color management is judging the actual impact of a major upgrade to a system that no professionals use at this time.

If a tree falls in the forest...

Let's face it, most professional color work is done in professional color applications. For production work that's typically an Adobe or Quark product and while they may give the user the option to select an outside color engine, people rarely do. It's end users that have been using ICM color conversions when they print and many printing systems licensed an outside CMM for those conversions anyway.

So does that mean that Vista color management is only going to change the consumer-level user? In the short term, I think yes. Especially as the current shortcomings in Vista's handling of display calibration and in WCS make it an unwise decision in professional color workflows. I'm sure Microsoft will eventually correct these problems in an upcoming 'service pack' but in the meantime consumer-level users will be the ones feting out WCS and that's OK with me. As much as we like change to happen quickly, the adoption of a major system upgrade is one that is often undertaken slowly.

Predictability - a bit of a wash

One of the concerns the ICC is addressing is predictability. If ICC profiles from different vendors are combined in a workflow, will they produce expected results? Vista's WCS combines color information into color transforms on the fly. While this technique makes for optimized gamut mapping how does it do for predictability? That remains to be seen. Suffice to say that both architectures are dealing with predictability in different ways and which one wins out remains to be seen.

Unknown capabilities (does it work?)

The color science and architecture behind WCS look good on paper. They've adopted acknowledged color science techniques and formulae such as CIECAM02. It should work well but as with any new system it remains to be seen if the implementation delivers on the promise.

Available only on Vista

As WCS is only available on Vista and will only be available on Vista, the adoption curve won't be too quick. Add to that the glacial pace of color management adoption in general and we will probably have something we'll be able to observe over many months. Again, this is probably a good thing.

Interactions with Photoshop:

Yes, I finally get around to the meat of the article that many people are looking for:

Can I get at WCS from Photoshop and how?

The short answer is yes, in some cases.

In Photoshop on Windows you have the ability to select "ICM" as the color engine for color transforms. When file conversions are performed, Photoshop will call on the operating system to perform the color calculations rather than its internal engine. So, a few points:

- Though "ICM" is what you select in Photoshop, WCS will be used if the selected (or embedded) profiles contain the MS00 tag which contain a WCS profile.

- Photoshop does NOT use ANY external engine to perform the image-to-screen conversion. So if an image's profile contains a WCS-embedded profile (I know, it gets convoluted), Photoshop will only use the ICC portion of the profile to display the image but will use the WCS portion of the profile when you convert the file to another color space or print with conversion. The chances of the WCS profile being radically different from its ICC 'host' are not too great but it could introduce some confusion and possible inconsistencies into your workflow.

In Summary

WCS has the makings of a very capable color management system. It seems to be able to fit into traditional ICC-based workflows and then quickly flip into WCS mode for some of its newer features and capabilities. The architecture certainly has a future. It's the present I am concerned with primarily. Due to Vista's non-handling and mishandling of graphics card calibration curves it is next to impossible for a professional user to be confident that their system is properly calibrated and displaying color correctly. For this reason I do not recommend Vista for professional workflows at this time. When Microsoft addresses the calibration-clobbering bug in a future service pack then I think Vista will make an effective platform for high quality color production.

For further reading:

Thanks for reading,

Steve Upton
Feb. 2007


In a visit to or, you opted to receive this newsletter. You may have also heard Steve Upton speak and requested more information. If you have received this message in error, we apologize. We value our relationship with you and do not want to spam you. See below for details on how to provide feedback, how to unsubscribe, or how to become a sponsor.

FEEDBACK and FAQs To submit questions or feedback to CHROMiX, email us at: colornews(at)
Please include your name, email address, and phone number in all correspondence.

SUBSCRIPTIONS To unsubscribe from CHROMiX ColorNews, reply to this message with "unsubscribe" in the subject.

To subscribe,
mailto:colornews(at) with "subscribe" in the subject.

For previous ColorNews articles follow this link:

Entire Contents of CHROMiX ColorNews (c)2006 CHROMiX, Inc. CHROMiX, ColorThink, ColorNews, ColorSmarts, ColorGear, ColorForums and are trademarks of CHROMiX Inc. All other trademarks are property of their respective owners. CHROMiX ColorNews is intended as an informative update to CHROMiX customers and business associates. We are not responsible for errors or omissions.