How We Test And Control Color

Why Is Color Important?

Successful products need to stand out in a crowded marketplace. One way to do this is with a great paint job or molded-in color. With modern paints and pigments, there are millions of colors to choose from. Colors attract attention, establish brand identity, differentiate your product, and help to create an emotional response for your customers.

X-Rite Color Tester at Star Rapid

As a manufacturer we strive to ensure our clients get exactly the paint color and shade that they want. But in practice, colors can’t always be exact due to a number of factors such as the availability of consistent colors from the pigment manufacturer, variability in processing conditions, local changes in temperature or humidity, and even the light source used for viewing. Traditionally these factors made the analysis of color highly subjective and imprecise, which is why we needed to find a better way.

X-Rite Color Tester at Star Rapid
The X-Rite must be calibrated against both black and white before each testing session.

How Do We Make Sure You Get The Right Color?

Many industries still rely on color matching by eye using sample chips, color swatches or the like. This method is not only subjective and inaccurate, but it’s impossible to provide quantifiable data that can be monitored during production and relayed to the customer. How do we verify the color that we apply to a part, while communicating this effectively not only within our organization but also in real time with the client? One of the ways we apply quality assurance to surface finish colors is with the X-Rite spectrophotometer.

What Is A Spectrophotometer?

A spectrophotometer is an instrument used to measure the reflected wavelength of energy from a target source and compare this to a known standard. Most of this energy is in the visible spectrum, with a little in the ultraviolet and near ultraviolet. Each wavelength represents an individual color in the LCH color space. LCH means light, chroma and hue. These are defined as numerical values, so it’s very useful when communicating color information objectively.

How Does The X-Rite Work?

The X-Rite has its own powerful light source with a known energy level. In operation, the unit shines this light off the target, and then reads the wavelength reflected from the surface. This reading is compared to the reference color, which is usually provided by the customer and programmed into the system’s memory. Reference colors can be updated or modified at any time.

X-Rite Color Tester at Star Rapid
The X-Rite can take a color reading even on small curved surfaces.

After a reading, the X-Rite stores this information for record keeping and reporting. It can be shared with the client or other team members, or uploaded to the cloud for worldwide supply chain management. The X-Rite can be programed to give a simple “pass/fail” verification for quick in-line quality checks, or provide more detailed spectral analysis for each color component to help fine tune process control parameters.

X-Rite Color Tester at Star Rapid
Color information is presented as Light, Chroma and Hue values.

Using Color Space For Process Control

A color space is one way to visualize a color reading. Color spaces are visualized as a three-dimensional zone, where each dimension represents one of the three LCH values.

X-Rite Color Tester at Star Rapid
The X-Rite takes reading based on the LCH color space.

Being able to quickly visualize individual readings within this space makes it easier for the operator to asses how an individual sample differs from the reference, both in magnitude and direction. This information is then used to control the process used to make the color, whether it’s painting, anodizing or plating.

X-Rite Color Tester at Star Rapid
Test readings appear as dots within the target zone.

Does The X-Rite Work On All Surfaces?

The X-Rite works on metals, plastics, fabrics, rubber, wood, ceramics and more. It works with smooth or rough textures, different levels of reflectivity, tints and hues. This versatility makes it invaluable for rapid prototyping and low-volume production, since we deal with such a wide range of products every day.

However, some surfaces are especially shiny with the addition of optical brightening agents (OBAs). These highly reflective surfaces can potentially throw a reading off when only using visible light. What to do then?

UV Calibrated Color Readings

Optical brighteners are effective only in the visible light spectrum, so the X-Rite also has a separate calibrated UV light source. This UV light is balanced with visible light to create a mixed source reading, which is immune to the effects of optical brighteners. This yields a more stable and reliable result.

X-Rite Color Tester at Star Rapid
The X-Rite is rechargeable and portable, so it can be used anywhere it’s needed.

How Does This Benefit You?

Ensuring color accuracy is an essential part of quality control and material verification. It helps to prevent mistakes while guaranteeing consistency lot-to-lot for higher volume production runs. Color accuracy is important to your brand identity, product positioning and your customer’s satisfaction. A quantifiable, unambiguous method for testing colors helps to streamline communications between you and your manufacturing partner, avoiding costly misunderstandings while improving process control for faster throughput at lower cost. Ultimately this provides you with peace of mind that you will get exactly the color that you specified without surprises. This is the kind of service that you can expect from us when you contact us for a free quotation and project review on your next great part.


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