Posted by Elaine Becker on Wed, Apr 28, 2010
CyberChrome Inc was an exhibitor at the recent American Coatings
Show in Charlotte, NC. Featured products included OnColor Profiler for improving inter-instrument agreement and the OnColor Suite of color management software for quality control and color formulation.
According to the press release from the American Coatings Society, "With 328 exhibitors and about 6,700 overall participants (2008: 331 / 5,600), the second edition of the American Coatings Show & Conference was hugely successful as the highlight event of the US paint and coatings industry. The combination of trade show and conference, held April 12-15, 2010 at the Charlotte Convention Center, North Carolina, thus once again exceeded all expectations."
Attendees came from not only North and South America, but there was a strong presence from Asia as well. Visitors at the CyberChrome booth included many US companies but also companies from Canada, Mexico, India, China, and other Pac Rim countries.
Interest in instrument profiling was high as companies struggle to manufacture to the same electronic color standards with tight color tolerances around the world. OnColor Profiler helps to meet the objective by providing much tighter inter-instrument agreement and allows them to meet the rigid color tolerances demanded in today's market.
Many larger companies are also interested in placing color matching systems at their distributor locations where they can match their own custom colors and reduce the burden on the color lab at the main facility. It also allows distributors to turn around custom matches in a much shorter time. CyberChrome's Match Express software provides an affordable and easy to use software package for distribution locations.
While attendance was "decent" at this show, exhibitors and attendees both wonder about the future of trade shows such as this one. With internet meetings, webinars, and the high costs of travel, it seems like fewer and fewer people attend these shows. There is still much to be said for face to face meeting, ralationship building and the social interaction that happens at events like this. What are your thoughts on attending trade shows in the future?
Posted by Elaine Becker on Thu, Jul 16, 2009
So many color disputes arise these days because color instruments don't necessarily read the same. Electronic color standards are widely used and shared within a supply chain and have many benefits, but if all of your instruments are not regularly monitored and are known to read the same, then problems can arise.
Many users assume that since they do a daily calibration on their instrument, their readings are correct. And if they are correct, then they must match every else's. That's not usually the case. Spectrophotometers from different suppliers may read color differently. Even with the same model from the same supplier, significant differences can be found depending on the age of the instrument and how well it is maintained.
In order for electronic standards to "work" within your supply chain, you need to be able to recall a stored standard, measure the actual stored standard on another instrument and have a resulting DE of 0.15 or less. The number of 0.15 is dependent on how tight your tolerances are. If you are trying to supply a color match that is < 0.5 DE, then you certainly don't want to have half of that deviation taken up by lack of inter-instrument agreement. A good rule of thumb is that no more than 25% of your tolerance should be given up to instrument variables (such as INTER-INSTRUMENT AGREEMENT, sample repeatability, and instrument repeatability). So if your tolerance is DE=1.0, then you can live with measurement uncertainty of up to 0.25 DE. If your tolerance is DE < 0.5, then you can live with an uncertainty of no more than 0.125. So as tolerances get tighter and supplies get more critical of color, INTER-INSTRUMENT AGREEMENT becomes more important. Instrument profiling can help you achieve the INTER-INSTRUMENT AGREEMENT that you need in order to meet these tight tolerances.
One advancement in color technology in use today is instrument profiling. Instrument profiling is used to make a population of spectrophotometers read to within a tighter specification of each other. A master instrument is used as the reference point and all other instruments are "cloned" to match this master instrument. A complex set of equations is used to profile or "correct" a target instrument so that its spectral data mimics that of the master. After profiling, all data taken on the target instrument is now corrected to match the master. The result is much tighter agreement between instruments which leads to fewer disputes over whether the color match is acceptable and faster acceptance and approval of submits.
Posted by Mike Burns on Thu, Jul 16, 2009
One of the more frequent questions we hear from suppliers is: What should my color tolerances be? The simple answer equates to what the client will accept in color variation in all directions of color space versus the color standard the supplier needs to match. The importance of the client providing representative color standards will be the subject of a future blog.
In the seventies and throughout the eighties the majority of suppliers relied on the CIELab defaults of +/- 0.5 for *a / *b axis with *L tolerances of +/- 1.0. The CIELab DeltaE default was 1.0. These so-called box tolerances were applied to dark colors, light colors, pastel colors, or high chroma colors with the assumption that regardless of where color was in color space any change in color perceptibility or color acceptability for the color match was the same. The issues with these default numerical tolerances were that the human eye could accept bigger differences in lightness and darkness of darker colors than in lighter colors. The same could be said of the hue (color of the sample). Light pastel colors were more susceptible to a noticeable color difference than darker colors. Consider a light beige where the color shifts a numerical 0.5 towards the -b* axis (bluer). Dependent on the product this shift may be unacceptable whereas in a dark brown or maroon color it may be totally acceptable. There have been shifts of Delta L* (Lightness) of 3.0+ units in a dark royal blue that have been totally acceptable whereas the Delta L* tolerance of 1.0 would indicate it was unacceptable. With these type analogies color scientists sought some way to apply weighting factors to better define color differences dependent on where the color was located in color space.
In the 1980's and 90's, color scientists developed improved color equations like CMC and later CIE2000 for determining a better way to define small color differences that were more perceptually uniform. Both equations use elliptical tolerancing to define an acceptability ellipse for a point in color space. The ellipses vary in shape and size throughout color space. Both CMC and CIE 2000 DE use weighting factors for lightness, chroma (CMC) and lightness, chroma, and hue (CIE2000) that better correlate to color differences asa the human eye sees it. The result over time has been that elliptical tolerances as defined by color difference equations like CMC and CIE2000 are widely preferred within the color industry as being superior in defining human color perceptibility and color acceptability. However, box tolerances are still in widespread use due to their ease of use and the long and extensive color histories that companies have bases on them.
There is no right or wrong answer. It's up to the buyer and seller to negotiate what is acceptable and to clearly spell it out in terms of a color specification.