Handheld spectrometer application for Surface Color Measuring

In a room without any light source, can you see the color of the apple that someone just passed it to you? In this simple test, we realized that in the absence of light environment, human vision cannot play a role and has no ability to judge colors. That is “Without light there is no color”.

Since there is no color when no light, then after having light, is there any problem of color identification? I believe you have had a similar experience about you buy a goods in red at the store but found that the color of the goods is not what you wished when you are home. This example tells us that different light source in different environment for human eye may receive different color from the object. So, is there any standard for color definition? Yes! Many designers they will use the color number to represent the standard red, bright red or wine red, these color code also helped the designer and the customer in the selection of color and avoided the disputes on color cognition.

UPRtek handheld spectrometer is being researched as a viable tool for measuring surface colors (as opposed to only light source) when UPRtek was collecting and writing this article in 2014. This has many ramifications in the market for standardizing and validating color matches for printed material, fabric color, component color uniformity, logo color compliance. This also has ramifications for studying Metamerism.

Metamerism

When comparing two color patches under one light source, the colors may match – but when you try it with another light source, they fail to match. This is an optical phenomenon called metamerism. A more practical example is where you pick out a shirt and pants in a department store because they have matching colors but when you wear it outside under daylight, the colors do not match anymore. The MK350 may be able to analyze this phenomenon and come to understand how light spectrum and surface reflectivity cause these problems.

Research of Measuring Surface Color

Measuring surface color varies widely with the source light. According to Professor MeiJun Lo of the Shih Hsin University (Taiwan), academic research is under way to determine if using spectrums from standard white baseline juxtaposed against a color patch can be mathematically combined to come up with a standardized color, in spite of the type of light source.

Peripheral Light Obscures Surface Measurement

Measuring colors on a surface with an MK350 device as shown (below) will let too much peripheral light in. Because the MK350 performs Cosine Correction your results will show a spectrum closer to the dominant light source. Trying to block out the peripheral light by pressing the lens up against the surface will block out all light and will only produce results for black.

Accessory Lens Tunnel Blocks Peripheral Light

UPRtek had researched to use an accessory device as shown below to block out peripheral light while capturing only the surface area in front. However, even with this procedure, you are still at the mercy of the source light colors.

Monitor the Brand Colors

Being able to measure surface colors will help companies monitor their brand colors, especially in the outdoors, where sunlight is apt to oxidize paints/inks and fade colors over time. Many companies are especially cognizant of displaying true brand colors and will be quick to replace them when color degradation falls below standards.

uSpectrum PC Software – Spectrum Analysis

The below color spectrum captured a white baseline swatch (blue line) and a red test swatch (yellow line) under an LED light using a test lens tunnel accessory of handheld spectrometer. You can use uSpectrum PC Software to process multiple colors analysis and comparison.