Color is the most immediately noticeable element of overall appearance, and the methods used to maintain color consistency between suppliers, products, and individual parts are known as color management. Originally the province of art departments and human visual appraisals, the importance of color management has now been recognized in almost every industry, and has driven the development of sophisticated instruments and techniques for removing subjectivity from the color discussion.

"Using reliable, precise instrumentation is the only way to objectify the perception of color and ensure that expensive mistakes are avoided in the production process," says Mike Gogoel, vice president and general manager at BYK-Gardner, Columbia, MD. Gogoel offered the following tips for selecting the right instruments for color management.

1. Choose Intuitive, Easy-to-Use Instrumentation

Industrial equipment, such as a colorimeter, is often clumsy and complex. Many instrument makers subscribe to a "whatever works" philosophy during the design process, but according to Gogoel, those instruments are not necessarily the best choice. Carefully designed, usable instrumentation can generate savings for businesses in the long run.

"No matter what type of instrumentation you're using," he says, "it's important to consider its design and operation. Intuitive instrumentation means less time and money spent on training and retraining, as well as increases in the speed of using the instruments. Especially in the current job market, where employees don't necessarily stay with a company for life, training savings on a device can be realized several times during its usable lifetime."

2. Test Instruments for Repeatability

Not all instruments are created equal, and some color-measurement devices may not offer the precision measurements needed to ensure exacting color reproduction across several batches or production runs. Look for colorimeters and spectrophotometers that offer close-tolerance repeatability - the ability of an instrument to measure color consistently across multiple samples. It's essential that your instruments be consistent, so that every measurement you take with them can be relied on. Look for repeatability within the low hundredths of cumulative color (DE) difference.

3. Choose Instruments That Offer High Rates of Reproducibility

Reproducibility is tested by measuring the same sample with multiple instruments to quantify any variation between the devices. It's an essential figure for any operation that uses more than one color measurement device, providing the assurance that color divergences in products don't arise due to slight measurement inconsistencies between devices. For reproducibility, tolerances between devices should be within the low tenths ±DE range.

"Beyond just calculating differences within an operation, reproducibility may be the most important factor when dealing with suppliers," Gogoel says. "The supplier relationship is built around matching up the numbers, so it's essential that you not only look for reproducibility among the devices you buy for your operation, but that you test for it with every supplier you have."

4. Ensure Instruments Have Sufficient Measurement Area

According to Gogoel, dispersion affects precision color measurements more than some might realize. Using a colorimeter that only offers a small measurement area can result in inaccuracies. Make sure that any instrumentation you purchase offers a measurement area sufficient for the samples and products you plan to check with it.

5. Look for Instruments That Can Perform Rapid Successive Measurements

Even when the measurement area is carefully considered, occasionally larger samples have to be dealt with. In these situations, a device that can perform a rapid series of sample measurements will greatly reduce time and cost. In addition, the best colorimeters offer a pass/fail mode, in which a set of tolerances can be stored in the device, allowing a number of subsequent samples to be rapidly passed or failed as within the specification. Many companies use this pass/fail mode to speed the color-testing process, or to allow workers with less training to achieve precise results when performing color tests.

6. Ensure Measurement Equipment Has On-Board Statistical Capabilities

Rapid measuring devices should provide statistical capabilities within the device, such as average, standard deviation and other statistics calculations. This allows the multiple measurements taken of a large sample to be quickly averaged to obtain an overall, useful measurement of color.

7. Consider Portable Instrumentation

The use of LED illumination in colorimeter design has brought the precision once only available with bench instruments to small portable packages. A portable colorimeter means samples and products can be color-checked on the production floor or in the field.

"The portable devices mean the end of production stoppages while products or samples are pulled off the line to be sent to the color lab for testing," Gogoel says. "With an accurate, portable device, the product can be checked right on the floor of your plant, as it's produced."

8. Investigate Instrument Durability

It's important to examine instrument endurance and durability, especially with portable colorimeters. A portable device can be used in a variety of places, and should be able to withstand all of those environments.

"Be sure to consider where the device will be used," Gogoel urges, "and what kind of stress, weather and the like it will need to stand up to. Portable devices may be needed anywhere from the plant to the field, and they may be handled by a variety of workers. Find out what warranties are offered, and check the overall quality of the instrument before you buy."

9. Consider the Impact of Ergonomics

Taking a look at ergonomics when you specify your instrumentation is a smart idea. With more and more attention being paid to industrial ergonomic impact, it's important to consider the design of the instruments you choose for color measurement. Not only can intelligent ergonomic design help increase the overall productivity of any employee working with the tool, but it can reduce insurance and worker's compensation costs as well.

10. Think About the Software You'll Use with the Instruments

Most color data will eventually make its way into a computer at some step in the process, and it's important to contemplate the software interface that the instrument provides. The best color-measurement devices will provide software and connectivity to common programs, such as Microsoft Excel(tm) for spreadsheets or Access(tm) for databases.

"The computer is a great tool for handling the data generated by color control and management," Gogoel says, "but not every instrument provides an easy method to get its data into the software you use. Make sure the device you choose will fit into your information system, and try to avoid costly proprietary software. Sticking with common formats, like Excel, makes dealing with color data far more simple, both internally, where employees are already trained, and externally, when exchanging data with customers and suppliers.

"Basically, care and attention to a few details will ensure that organizations get the instruments they need to manage color across their suppliers, their production process, and their customers," Gogoel says.