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| The
Pantone® Color Cue is a hand-held instrument used to measure the color of
an object and display the closest Pantone (PMS) ink color match.
Since arcade game cabinets have always been painted, determining the
closest ink color is not directly useful if the goal is to obtain paint to
match the original factory colors. But the convenience and accuracy
of the Color Cue device makes it worth some additional effort to make it a
more useful tool for this task.
Here's what we will be covering on this page: |
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For a more general discussion of matching cabinet paint colors, see the color matching page on this web site.
Color 101
The Pantone Matching System (PMS) has been around since the early 1960's and has been the industry standard for matching solid ink colors. The two main color printing methods are "solid" and "process, CMYK or four-color process". Solid (sometimes called "spot color") printing uses inks mixed to match each individual color. If a document has three colors, the press is set up with three colors of ink to match those colors. If the colors are referenced to particular PMS colors, the formulas for the inks are uniformly defined by Pantone so the colors will (in theory) always match. Process color printing uses mixtures of four colors (cyan, magenta, yellow and black) to make up a very wide range of colors. By printing these four colors in different intensities, thousands of different colors can be created. The art of color printing can fill (and has filled) many books, so we'll just cover some basic issues here.
Gamut, Color Space and the Human Eye
The human eye can discern many thousands if not millions of distinct colors, so color matching is no easy task. Inks and paints are combinations of dyes, pigments and other chemicals that filter the light that falls upon it to create colors. They do this by selectively absorbing or reflecting light depending on its wavelength within the visible light spectrum.
The Pantone color matching system currently contains 1114 distinct solid colors. Their process color guide covers over 3000 CMYK colors, although the CMYK process can create more than 3000 possible colors. However, the larger number of distinct process (CMYK) colors does not mean that a wider range of colors can be represented. In fact, the opposite is true. The 1114 distinct PMS colors generally cover a wider range of colors than the CMYK process can normally reproduce. This is evidenced by another useful product from Pantone: the Pantone Color Bridge (formerly called the Pantone Solid to Process Guide). The Pantone Color Bridge shows how each of the 1114 solid colors look when printed using standard CMYK process inks, and the difference between them are sometimes significant. Fancier inkjet printers can use six or more colors in order to print a wider range of colors, but this usually affects only the internal operation of the printing mechanism. The color information sent to the printer is the same, but with the additional ink colors available, the printer does a better job of reproducing them.
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The four-color CMYK process has a narrower "gamut", or range of colors that can be reproduced, as compared to the range of colors available as PMS solid colors. This makes sense because all CMYK colors are formed from just those four ink colors, while the PMS solid colors are mixed from a larger pool of ink colors (base + tints). So the irony is that even though there are more "possible" process colors, there are many PMS solid colors that can't be reproduced very accurately using CMYK process printing. Why all this detail? Well, the primary function of the Pantone Color Cue device is to measure and present the closest PMS solid color, but this might not be exactly what we need or want. More on that later. | ||
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A: Human eye color gamut |
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What about RGB?
Paints and inks use subtractive color models, since individual pigments selectively absorb different frequencies. If you mix two different pigments, they each absorb their own colors so the resulting color is the color of the light source minus all of the colors absorbed by the pigments. The red-green-blue (RGB) color model used in the television and computer displays is an additive color model. The display emits specific colors rather than absorbs them, so the result of multiple color transmissions is the sum of all of the color sources.
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So for this discussion, the RGB color space doesn't help us very much. But since the gamut of RGB colors is at least as wide as all of the others so far, we can translate other colors into RGB and out again without losing much information. Note that doing the opposite (e.g. translating an arbitrary RGB color into a PMS solid color) may drastically change the resultant color. RGB colors are usually represented by the values of 0 to 255 for each of red, green and blue (or their hexadecimal equivalents of 00 to FF). While this is very convenient for computers, and is more than accurate enough for our color matching purposes, there are a number of even more accurate color space models, and for the most accurate use of the Pantone Color Cue, none of RGB, PMS or CMYK is the best.
Geek Time
The RGB color space was developed because it corresponds to the three colors that the human eye can detect, and it corresponds (not coincidentally) with the transmission colors of the vast majority of television and computer displays. RGB assumes a linear relationship of chroma and luminosity (50% red, 50% green and 50% blue should correspond to 50% gray), but human color perception is not linear in either of those relationships. So all color rendering systems include gamma correction factors in an attempt to translate the linear RGB color space to the non-linear color response of the human eye. This gamma correction is a necessary part of color rendering, but it is not part of the RGB specification. The Color Cue can display RGB values as sRGB, which incorporates an industry-standard gamma correction profile, or colors can be displayed as AdobeRGB, using Adobe's RGB gamma correction, which provides a wider color space than sRGB. The take-away from all this is that RGB is a reassuringly simple way of representing colors, but as is the case with the Pantone Color Matching system, the answer that you end up with may not necessarily be what you want.
The Pantone Color Cue is capable of displaying the measured color in a variety of color spaces, but as we will see later, the most accurate color measurements can only be displayed in two other color spaces: CIE L*a*b* and XYZ (tristimulus). Follow the links for a description of how these color spaces work, but suffice to say that they all simply render the measured color into three separate numbers. It's the mathematical representation of the particular color space that determines the significance of the numbers. So when we get to using the Color Cue in its most accurate mode, we will be switching to one of these alternate color spaces - not because we need so much color-measuring accuracy, but that's how we get the Color Cue to work in its higher resolution mode. More on that a little later.
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Gamut |
Number of possible colors |
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PMS Solid Colors |
Medium |
Currently 1114 |
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CMYK Process Colors |
Narrow |
Thousands to millions |
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Typical Paints |
Narrowest |
Hundreds to thousands |
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RGB |
Wide |
16 million |
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| L*a*b* or XYZ | Wider | Millions | ||
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Human Eye |
Widest |
Millions |
Pantone Color Cue Basic Operations
The Pantone Color Cue is an amazing device, and with some menu setting adjustments, it can be even more useful for paint color matching. Here's how the Color Cue works "out of the box". Turn it on, put it on top of the color you want to measure, press the button and the LCD tells you the closest Pantone PMS color. Incredible. If pinball machine cabinets used Pantone inks, the problem of color matching would be completely solved, because this device would identify the original color that was used, which you could then simply re-apply. However, there are two problems:
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Pinball machines did not use Pantone PMS color matching since they were painted, not printed with inks. If there ever were "color codes" for the original colors, they are (so far) lost in time, and even if they existed, they would be formulas that only applied to the factory's original paint suppliers. So, we can now find the nearest PMS color, but that does not necessarily make it a perfect (or even a very good) match.
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The PMS color that the Color Cue returns is the closest PMS color from the universe of 1114 PMS solid colors. That's not really a whole lot of colors to choose from. The sensor inside the Color Cue can detect over 10 million colors, but the default information that it displays only shows the closest PMS color. You can step through the Color Cue's other data displays and it will show you the measured color in a bunch of other formats and color spaces, like RGB, CMYK and even L*a*b*, but here's the catch: these numbers are only look-up values for the PMS color that has been chosen. You can see this yourself by making multiple measurements over an area where the color gradually lightens or darkens. The Color Cue will show a different PMS color at a certain point, but the numbers for other color display formats won't change at all until the PMS color also changes.
| So,
it's extremely easy to get basic color information using the Color Cue,
and once you find a way to get the paint that you need based on the color
reported by the Color Cue (more on that below), you're already way ahead
of the game. But, there are some changes that you can make to the
Color Cue's configuration that can help you make more accurate color
measurements for cases where you don't necessarily want to end up with a
PMS color, like us.
The picture to the right shows the underside of the Color Cue device, showing the color sensor (the blue tinted object) and some of the illumination LEDs. |
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Getting More Accurate Color Information from the Color Cue
When you press the measurement button on the Color Cue, the results are displayed instantly on the LCD. When you press the "next" button, the color is displayed in a number of different formats, such as CMYK, sRGB, Adobe-compatible RGB, and more. We can turn off some of the less useful formats and there are also some measurement display formats that default to "off" that we will want to turn on. Here are the recommended changes:
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In the Display Data menu, turn off CMYK, EuroCMYK, CMYKOG, sRGB100%, sRGB HTML, all the Adobe modes, L*a*b*, XYZ and FormulaGuide. Leave on sRGB255.
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In the Special Options menu, go to Set Display and turn on Display Lab, Display XYZ, Display dE and Display Name.
The Color Cue will still display the closest PMS color, but now when you press the "next" button you will be able to see the raw color measurements coming from the color sensor. This is evident by taking multiple measurements at slightly different spots. Typically, the same PMS color will come up, but if you look at the other data display types (other than sRGB255), you will see that they change slightly each time.
You have also turned on the Display dE option, which shows up as a number after "dE=" in the LCD. This number indicates how far away the measured color is from the PMS color number that is displayed. Roughly, a dE number less than 1 is undetectably different, and numbers greater than 1 indicate approximately the number of discernable hues in between the measured color and the reported PMS color. It's surprising sometimes how far off the PMS color is from the measured paint color.
If you get a dE number of 1.0 or less, the PMS color is accurate for any color-matching tasks. In those cases, you can take either the PMS color number or the sRGB255 values as the color that you want to match up with paint. If the dE number is greater than 1.0, you should use the more accurate iLab or iXYZ values instead. Don't use the sRGB255 values in this case because the sRGB255 value is rounded to the nearest PMS color, not the measured color (which you know are significantly different because if the dE is greater than 1.0). The iLab data display typically looks like this:
iLab=FDDFE900A
95.4 -0.3 -1.3
This corresponds to L = 95.4, a = -0.3 and b = -1.3. For iXYZ, the data display may look like this:
iXYZ=
8290 8819 9667
This corresponds to X = 82.90, Y = 88.19 and Z = 96.67. There apparently wasn't room in the LCD for the decimal points, so you need to add them yourself.
So once you've transcribed the most accurate color codes, the next step is to match them to a paint color. Thanks to some nifty web sites out there, you can easily convert the less common XYZ and L*a*b* color formats to RGB, and from RGB we can actually go for a paint color match. If you're interested in learning more about color space conversion, here's the Wikipedia entry for the CIE Lab color space.
"Matching" Cabinet Colors with Modern Paints
We are often asked for paint color codes and for sources to obtain the right type and color paint for re-painting pinball machine cabinets. These are very difficult questions to answer on an individual basis and they are impossible to give answers that would apply to everyone. Here are some of the issues that can vary from case to case:
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Paint type: latex, oil, lacquer?
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Air gun or spray can or roller?
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What paint suppliers are available locally / what brands of paint?
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What color matching capabilities are available from your paint supplier?
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Are you going for a "factory new" or a "slightly aged" look?
Some paint suppliers may be able to work from RGB or PMS color descriptions, but most would probably be baffled, confused, or they would just screw it up. So from here on, all we can offer are a number of suggestions. Don't miss the last one - it's an incredible on-line resource!
If your paint store can't deal with PMS or RGB color specifications, can they read the color from a color sample? If so, and you happen to have a Pantone color swatch book, they can simply scan that one in and you're done. Or, you could print a sample of the color if you have a good photo quality inkjet printer. Just keep in mind that your printer may have difficulties with certain bright or highly saturated colors.
There are many web sites that offer Pantone color charts, or color charts based on RGB values. And many paint stores can provide free paint chip samples. You could bring back the color samples and compare them to the on-screen samples that correspond to the colors you want to match. This is easier said than done, since it's hard to get the lighting of the paint sample right, and your monitor's color calibration may be off. Still, this could get you close if the other methods won't work.
And now for the silver bullet: Go to http://easyrgb.com/ and you can use the color calculator to convert your L*a*b* or XYZ values to RGB, and you can use their color matching page to match any RGB color to a number of well-known brands of paints, such as Benjamin Moore, Dutch Boy, PPG and Sherwin Williams. Simply enter the RGB values, select the brand of paint, and then you get a color chart showing the RGB color next to the four closest paint color matches. These guys deserve a prize for putting this together!
We have used the process above to add paint formulas for a number of pinball machine cabinets to the main color matching page here. As time goes on, we will measure more cabinet colors and post the results there as well.
Pantone® is a registered trademark of Pantone, Inc., Carlstadt, NJ USA
If you have additions, corrections, comments or other information that you would like to see on this page, please let us know.