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CHROMiX ColorNews Issue #21 - The Color Key

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Type: ColorNews
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Welcome to ColorNews, a periodic update on things related to Color Management. We are striving for a regular consistent newsletter of high value to our customers. Please let us know what your interests are so we can address these concerns in our coming issues.


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

Issue #21
October 18th, 2005


A few Quick Notes of Interest:

** GretagMacbeth and CHROMiX have launched the Eye-One Customer Loyalty Program (CLP) to help past Eye-One Pro customers upgrade to the new RevB Eye-One Pro (shipping since April 2005), and allow users of past Eye-One Pro packages to acquire the additional software modules not previously available in their original Eye-One Pro purchase. See details below in CHROMiX News.

** The CHROMiX Color Management Utility Kit special continues. Here's the deal: when you buy either an Eye-One Pro solution or an X-Rite Pulse ColorElite solution, CHROMiX will send you a FREE Color Management Kit. See ad for details below.

** TRADE in your old measurement device and get up to $200 off your next GretagMacbeth Eye-One purchase! See details in ad below.

** "The color Key" - an article by CHROMiX President Steve Upton

** X-Rite Free Accessory Kit promotion ends October 31st. If you are considering an X-Rite Pulse we suggest you act quickly as the free promotion ends soon!
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Table of Contents


1. CHROMiX News
2. Color, Product & Industry News
3. Shows and Events
4. Tech & Education Notes
5. "The color Key" - an article by CHROMiX President Steve Upton
6. CHROMiX Open Box items for sale
7. ColorNews Administration (feedback, subscriptions, etc.)




Since our last ColorNews Issue #20 on September 7th, 2005, here's what's been happening at CHROMiX:

We are pleased to be working closely with GretagMacbeth on the Eye-One CUSTOMER LOYALTY PROGRAM. Regardless of where you bought your Eye-One Pro, this program allows you to upgrade to the newest hardware and software at substantial savings. For example, if you bought your old Eye-One Pro solution in year:
2001/2002 then your savings would be 30% off List Price of the new Eye-One solution
2003 then your savings would be 40% off List Price of the new Eye-One solution
2004/2005 then your savings would be 50% off List Price of the new Eye-One solution
For details of the program or more information, call ColorGear Sales at 866-CHROMiX x1, email sales (at) or go to our website
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One more step in the progression
CHROMiX is very pleased to be beta testing COLORTHINK PRO ! We will do everything we can to ensure that this final stage will go smoothly and that we'll be able to finish the product for release soon. Stay tuned..

CHROMiX's President, Steve Upton will be demonstrating ColorThink Pro at PHOTO PLUS EXPO 2005 at Javits Convention Center, New York from October 20-22. He'll be in the Eizo booth # 775. Using ColorThink Pro, Steve will be giving presentations regarding workflow, advanced profiling tool concepts, and profile evaluation. Come by and talk with him or get a demonstration of our newest software if you are attending the Expo.
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CHROMiX has had a great initial response to the new Kodak ColorFlow Custom Color Tools profile editor. Custom Color Tools is a Photoshop plug-in that allows editing of output profiles using the Photoshop editing tools we are all know. Until now, this great editor has been very difficult to find. Now you can order it easily from our site, anytime. (Mac OS X-only)
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ColorThink 2.2b17 beta is now available. It is a free update to the current ColorThink software. We continue to add fixes and look for feedback from our users. Download a copy, give it a try, and let us know what you think.
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CHROMiX has added Red River Paper and iVivid to our growing list of OEM partners. These are two outstanding companies that CHROMiX is supplying high quality profiles for. If you're an organization, association, manufacturer, or large end user, give us a call to discuss how we can customize a profiling program to meet your customers' and/or company's needs. Call Rick Hatmaker directly at (206) 985-9844.


Color, Product & Industry News


GretagMacbeth Customer Loyalty Program is here! The Loyalty Program is designed to help Eye-One Pro owners to upgrade to the new RevB Eye-One Pro (shipping since April 2005), and acquire the additional software modules not previously available in their original Eye-One Pro purchase. Users can enjoy savings from 30%, 40% to 50% off the new Eye-One Pro packages. For more information go to:
Click here

GretagMacbeth has released Eye-One Match v3.3 for Windows and Mac. The new version adds the long-awaited profile editing module to the software. A new scanning ruler, a new backing board and a new soft case will be bundled with the Eye-One.

Beginning week October 31: Eye-One Ruler and Softcase upgrade kits will be available for use with any Eye-One. You can order them now here:
Click here

Rumor has it that the Eye-One IO from GretagMacbeth may actually start shipping early November. This has been a long awaited X/Y scanning table that will automate scanning target charts using the ever popular Eye-One Pro spectrophotometer. CHROMiX has been testing this baby, and we must say that it is so fast using the new RevB Eye-One Pro device that we were amazed. We've done some tests, and found that the IO scanned an IT8 target a little over 2 minutes - almost noiselessly!! The iO can be used with any Eye-One Pro device but to obtain this speed, the rev B version is required - see the GretagMacbeth Customer Loyalty Program for details about upgrading your Eye-One. The Eye-One IO is set to be priced at $2000.

Epson has developed an application called ColorBase v1.1 for the Stylus Photo R2400 and Stylus Pro 4800/7800/9800 printers that allows color output to be calibrated to match that of Epson's reference printer for each model. ColorBase has Mac and Windows versions and is a free download from various Epson web sites.

Adobe released v3.2 of the Camera Raw plug-in for Photoshop CS2. Version 3.2 adds support for the Nikon D2Hs, D70s and D50, Leica's Digital-Module-R back and the Hasselblad H2D. Also, Camera Raw now fully honors the 'As Shot' white balance (WB) for D2X, thanks to cooperation from Nikon.

Microsoft and Canon announced joint implementation of some of the core technologies inside the Windows Color System (WCS), which is the ambitious new color management architecture in the upcoming Vista operating system. The technology has features promising "better screen-to-print matching, better overall color appearance, and support for higher fidelity printing..."




October 20 - 22, 2005, PhotoPLUS EXPO Photography & Design Conference, Javits Convention Center, New York, NY. This is the largest and most comprehensive expo in the photographic and imaging industries. CHROMiX will be exhibiting in the Eizo booth #775. Steve Upton will be demonstrating CHROMiX's newest product, ColorThink Pro. Using ColorThink Pro, he will be giving presentations regarding workflow, advanced profiling tool concepts, and profile evaluation. Come by and talk with him and get a demonstration of our newest software if you are attending the Expo.
Click here

November 1 - 4, 2005, The Creative Suite Conference, Sydney, Australia, offers training and conferences specific to Adobe Creative Suite products (Adobe Photoshop, InDesign, Illustrator, Acrobat or GoLive). Looking for an excuse to get to Australia? This is the one.
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November 29 - December 2, 2005, Seybold San Francisco at The Palace Hotel, San Francisco, CA.
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December 4-6, 2005, PIA/GATF Color Management Conference at The Pointe Hilton Tapatio Cliffs Resort, Phoenix, AZ. This is the largest US show with exclusive focus on color management technology. Hear about the latest tools, workflows, and trends in producing high-quality color. Steve Upton of CHROMiX is speaking in sessions and labs ranging from 'Photoshop Usage' to 'Profile Verification Tools and Analysis' and 'Tools of the Trade-Under the Hood'. Hear Steve and other great speakers at the only conference focusing entirely on color management. For more details:
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January 9 - 13, 2006, MacWorld Conference and Expo at San Francisco's Moscone Center, San Francisco, CA.
This is the #1 event for Mac users and devotees in the world.
Click here


Tech & Education Notes


Since many of our readers are photographers, we thought we would mention a very good article at Creative Pro titled 'Digital Photography How-To: The Pros and Cons of Lens Flare', from Cambridge in Colour, by Sean T. McHugh. Although this excerpt doesn't focus on color management science specifically, this is relevant information for a common photography problem.
Click here

Not sure where else to put this one....
There's a significant buzz surrounding Microsoft's recent and upcoming Color Management efforts. We found an on-line article with a humorous, but relevant perspective on the matter from Edmund Ronald at Publish. It is titled 'Microsoft: The Bull in the Color Shop' and is at:
Click here



"The color Key" - an article by CHROMiX President Steve Upton


The color Key

If you work long enough in or near the print industry you start to take CMYK for granted. Especially K.

In looking over my previous articles I noticed that I had yet to cover the topic of K so it seemed like it was time.

The K in CMYK stands for "Key", NOT black as many might have you believe. The Key plate, in traditional color separations, is the plate that holds the detail in the image. In CMYK this is usually done with black ink.

In the modern color-managed workflow, an RGB image has an associated profile so each RGB number combination can be converted to a defined Lab color. This is fairly straight-forward and repeatable. When creating a CMYK combination to represent that color on output, things get considerably more complicated.

Lets talk a bit about how color is created using CMYK. If you apply yellow ink to paper, your color range starts at paper white and then becomes more yellow and saturated with the more ink you apply. But once you get to 100% yellow there's nothing more you can do without adding other inks. If you are looking for a medium-dark yellow you now have a whole host of choices to get it. First, you can add cyan and magenta ink. They are both required in order to offset each ink's tendency to move the color toward green or red. The addition of cyan and magenta does darken the yellow but they are also, together, blue - which is anti-yellow. So this addition of blue desaturates the yellow ink quickly, limiting the range of dark yellow colors available. A second choice is to add black ink. As black is added, the yellow darkens but is not desaturated nearly as quickly. This can result in a greater gamut of dark yellows.

When CMYK colors are created in normal workflows, either or both of these techniques are used. In fact, for a single original RGB color, many different combinations of CMYK can be used to (theoretically) create the same color on press.

So how do we decide which one to use? How much black should be used instead of CMY? The answer, as you should already guess, is the classic color management answer: "It depends".

Lets cover a bit more technique and terminology first.

Cyan, magenta and yellow inks used for offset printing are not pure enough colorants to be mixable in equal amounts for gray. The SWOP standard expects 50% cyan and 40% each magenta and yellow inks to produce a neutral gray. So let's say we had a CMY color of 60, 50, 40. In theory, if we removed the components of the color that produced gray (50,40,40) we would then be left with (10,10,0). If we then add enough black ink to bring us down to the same darkness (about 54% K), we have the CMYK combination of 10,10,0,54 that should appear very close to the original color yet is composed of VERY different amounts of ink! The total ink used drops from 150% to 74% AND changes from the more expensive color inks to black ink.

This kind of color replacement is called Gray Component Replacement (GCR). If the color range affected by this replacement is limited to dark, near-neutral colors, then it is called Under Color Removal (UCR). GCR, on the other hand, can be applied to neutral and non-neutral colors that are either light or dark. That brings us back to the "how much?" and "when?" questions.

It's probably best to cover this next section in point form:

Black start / max / width

In ICC profiles, the black generation method and amount is chosen at the time the profile is calculated and "baked" into the profile. For flexibility, we suggest calculating several profiles from the same measurements; each with different black generation settings (this is what we do with our ColorValet press profiling service). Black Start is the amount of cyan ink where black starts replacing other inks. For instance, a black start of 10 means that when cyan ink is less than 10%, CMY will be the only inks used to create colors, but for any colors where cyan is greater than 10%, K will replace some component of the color. Black Max is how high you want the K level to get in the resulting color. If you find your shadows are plugging, reducing Max K can help. Finally, black width is how far "out" into the saturated colors you want black to be substituted. A low black width will limit K substitution to near-neutral colors (similar to UCR). A high black width will allow substitution much farther out into the saturated colors. If you find your saturated colors look muddy, try lowering your black width.

Dot Gain vs color stability
Here are a few basic facts about printing (unsubstantiated, I admit, there's just not enough space here). Color casts, especially in neutrals, are the single most common (color) reason customers refuse print jobs. Dot gain varies due to press fluctuation the most in the mid tones of each channel - ranging from 40-60% - and the variance can differ from channel to channel. This means that when neutral colors have CMY inks that are in the range of 40-60%, they have a fairly good chance of shifting on press. Our example color of 60,50,40 has all three inks in the "danger zone" and so could be quite unstable on press. The converted color of 10,10,0,54 however, has only the black ink in the danger zone and changes in black dot gain won't create a color shift. (Thanks to Dan Remaley of the PIA/GATF for turning the light bulb on for me with this issue.)

Print job stability on press VS adjustment on press
With the above explanation in mind, you might think that GCR should be used heavily in all images, and yet many printers recommend light GCR or UCR. Why? Well, the very same reason you would use GCR - stability of color on press - makes it very difficult to change color on press. Many printers don't trust their customers' color management or separations and so they want the ability to adjust the job on press. GCR IS a very good thing. Just remember that if you use it, ensure that the color in the file is good (verified with an effective soft / hard proofing system) and that the printer can print according to the specs that defined your separation. If they are nowhere near SWOP, or your files are not well color managed, sending them high GCR files is going to cause problems. Or, more correctly, will limit their ability to correct problems. (of course, exchange the "you"s and "them"s if you are the printer)

Ink Speckling
In offset printing, the line screens for each channel tend to be the same or very close. When black is used in highlight colors, the dot size and shape is similar to the other inks and doesn't typically cause any problems. Inkjet printers using light cyan and light magenta are a different story. Highlight colors on inkjets are often built from CMY inks only. Inkjets that don't use Epson's UltraChrome inkset have no light black (gray) ink. If GCR is used in the highlight colors, the dark black ink exposes the true resolution of the printer, creating speckles that people often mistake for lowering of the printer's resolution. On these systems, use a black start value of 40-50% to keep K out of the highlights. This means that the careful balance of CMY is required for light colors - beware that color balance failure (often mistakenly called metamerism) might cause problems. Also, your profiling target had better effectively sample CMY-only near-neutral colors or your profiling software has little hope in finding how to print neutral highlights. I bet you've seen this problem as well.

Ink costs & drying time
This one is pretty simple. Less ink = less money AND less dry time. GCR = less ink so it saves both time and money.

If you think back to the dark yellow example above, recall that to build dark colors we could either add cyan / magenta to yellow OR add black. The difference to the size of the shadow gamut (the number and saturation of dark colors available) is significant. Black slowly desaturates yellow as it darkens it. In comparison, the blueish cyan/magenta mixture darkens and quickly desaturates yellow because it cancels it out. The result is many more saturated dark yellows when black is used rather than cyan/magenta. If you haven't realized it yet, dark-yellow is brown, and having full saturation in browns means wood, leather, and hair or flesh tones as they fall into shadow look MUCH better. If you are missing your browns, the profile will desaturate them into becoming more gray and you will be disappointed in your wood and leather and often see sharp transitions as faces and hair fall into shadow... sound familiar?

ColorThink Pro has a new graphing feature, Constrain Channels, which features sliders that allow you to "pull back" color channels individually. Pulling the K channel back to 0 is an interesting demonstration of how important black is to the gamut of a press. The gamut size is reduced by 20 to 30%.

Muddying saturated colors
The use of too much black in saturated colors can "muddy them up" on some printing systems. See Black Width above.

Restricting black replacement to neutrals is what UCR is all about. GCR came along later and extended this technique beyond the neutrals and into the colors. If done correctly, GCR can be very effective and improve image quality. Early GCR didn't always work as expected and many fell back to UCR for safety. GCR is now at the point where it is reliable and effective, and UCR is falling out of use. As the function of UCR is a special case of GCR (dark neutrals only), I expect the term UCR will fall out of use and we will refer to all black replacement as GCR.

Rich black
100% K is not typically the darkest color you can get from a printer or press. When Cyan and other inks are added, the darkness can often drop noticeably (from an L* value of 19 down to 9 in SWOP TR001 for instance). The combined color can either be neutral or have an intended hint of color. Blue blacks are popular as well as warm blacks and tend to be used differently in different cultures and parts of the world. Some profiling packages allow you to select the combination of inks for "max black".

Standard vs Custom separation profiles
As I mentioned above, the black generation method and amounts are set at the time of profile generation. They are not changeable on-the-fly as many would like. This is a limitation of the current ICC profile architecture. The profiles that ship with Adobe publishing products are high-quality and some are based on published standards, such as US Sheetfed Coated v2, but there is only one profile for each printing condition. This means Adobe chose a middle-of-the-road group of GCR settings when the profile was originally created. Color images vary widely and different levels of black generation should be used for each image type. Images that are predominantly neutral should typically have more GCR than those with many saturated colors. Flesh tones benefit from GCR but too much makes them appear muddy on press. Because of the baked-in limitation of ICC profiles it's best to keep a group of press profiles on hand so you can vary your black generation optimally.

As you can see, the subject of black is large and I haven't really scratched the surface. Suffice to say that "that extra channel" adds a lot of depth to color printing both in the color sense and in the number of choices we have and the number of topics there are to study. I hope I've at least opened your eyes to some of the effects of black and black generation. As always, I'm open to comments and more information if you have it.

Thanks for reading,

Steve Upton
October 18, 2005

For previous ColorNews articles follow this link:
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