Color Sensors vs. Contrast Sensors: Key Considerations

Wednesday, February 17, 2021

Which Sensor is Best for Your Application?

contrast sensors color sensorsColor sensors and contrast sensors are two common industrial automation solutions used in production environments today. You may even already have multiple color or contrast sensors in use in your environment. But with production lines today facing more frequent changes to meet consumer demands, you may find yourself in a situation where you’re needing to change your sensor setup due to a new product entering the line, multiple goods being produced in one environment, or some other challenge.

In this situation, the sensor solution you have in place may no longer be the ideal one for the job. Often, a product with certain properties might call for a color sensor and another product might call for a contrast sensor, and vice versa. Using the right sensor in these instances will make all the difference in supporting your goals of increasing production output, improving quality, reducing errors and waste, and other related objectives.

Choosing the right solution between color sensors and contrast sensors comes down to the product or material, its attributes, and what your overall production goals are. Here, we’ll explore four aspects of your products and production line to help you determine whether to invest in color sensors or contrast sensors.

4 Considerations for Choosing Between Color Sensors and Contrast Sensors

Verifying and/or Detecting Color

When you’re trying to detect or verify the value of a certain color on your product or material, you must first consider the production line and what you’re trying to achieve. This is important because, while you’re still trying to sense color, one solution may be better than the other.

For example, if you’re detecting or verifying a color that falls within a certain threshold, color sensors would be the ideal solution. This is because they can sense a range of colors, and once you set the threshold, color sensors can validate whether the color value of the product does or does not fall within that range. Contrast sensors would not be useful here because they can only sense colors within a grayscale range.

On the other hand, if you’re trying to verify that color is consistent and isn’t changing, then contrast sensors would be the best option. Contrast sensors convert colors to grayscale, so if the target object is meant to be consistent in terms of color, these sensors would be able to rapidly confirm this — or otherwise send a signal that there’s a problem.

Detecting Surface Finish

Ensuring that your products have a consistent surface finish as they move through your production line is essential for quality, but what that finish is will determine the ideal sensor used to detect it. This is because glossy and matte surfaces reflect light differently.

Glossy finishes reflect more light and can do so differently based on the position of the product and degree of glossiness, whereas matte finishes have more consistent light distribution. If your goal is to ensure that the products have a consistent surface finish, contrast sensors will be the most ideal solution due to the uniformity of the light distribution, particularly for matte finishes.

Detecting Color in Transparent Materials

If you manufacture different types of containers or bottles using materials containing color, ensuring the consistency of that color is essential for quality and your brand. This can occur in upstream and downstream phases of production, but most often, it begins with preforms. Because they’re transparent and feature a specific color, a contrast sensor won’t be the best option. What’s needed in this instance is a color sensor that works with transparent targets.

For example, EMX Industries manufactures the ColorMax VIEW line of color sensors designed to work with transparent targets. It features a detached light source for more flexibility during setup and a lightning-fast 20 kHz switching frequency — making it ideal for high-volume, high-speed production lines where numerous transparent or translucent containers of the same color must be verified for color accuracy.

Target Speed

While this isn’t a property of the target object itself, considering the speed of your production line is essential for success. There are a variety of color sensors and contrast sensors with different response times. Contrast sensors tend to have more rapid response rates. For example, if you have a high-speed production line and are simply looking to verify that the target has a matte surface, a contrast sensor would be the right choice.

Again, deciding between color sensors and contrast sensors comes down to the application. For example, if your target is a transparent container with a blue color, then a color sensor designed to work with these traits would be the best choice. High-speed options are available for many color sensor types.

Work with an Industry Leader to Find the Right Sensor

EMX Industries is a leading designer and manufacturer of both color sensors and contrast sensors. On the color side, our ColorMax line of sensors features a number of different models based on your application, including the ColorMax 1000 for opaque targets and ColorMax VIEW for transparent materials. We also offer a full line of specialty contrast sensors — the CNTX series — with varying spot sizes, operating ranges, and other advanced features.

Our sensors are advanced yet often more cost-effective than competing sensor solutions and expensive machine vision systems. Their ease of use, wide range of configuration options, accessories, and more make them the best choice for organizations looking to address their color and contrast sensing needs quickly and easily. And of course, every sensor comes backed by best-in-class technical support and customer service.

Get the Right Sensor for Your Application

Not sure whether a color or contrast sensor is right for your target material? We’ll conduct free testing on a sample of your material and provide a written report documenting its performance. Simply ship the materials to us, and we’ll take care of the rest!

Submit your complimentary sample analysis request today.