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Tuesday, April 8, 2014

Spectrometer

Spectrometer (spectrophotometer) is an instrument for measuring color. This tool is used to help people to check the color the color. This device is quite common used at the industries that deal with color such as:  printing, textile, garment and finishing materials. Lately this tool is also used in the furniture industry and wood finishing industry.
This tool is created to help people to check the color. At the beginning the checking of colors was visually done by human. In the industries that deals with color there was QC person that works to check the color to make sure the production is constantly stable. But then people started to realize that checking color by human being could lead to the inconsistency problem.
Here are some disadvantages of color observation by human being.
  • Every person has different sensitivity to the color.
The fact is every person has different sensitivity to see the color; some peoples may have high sensitivity to the green color, while some other people could be more sensitive to the red color, etc., some certain people even cannot distinguish some certain colors (the color blind people). In the manufacturing process it could become problem. If we have some (more than one) QC to keep the production quality, then every QC person could give different result. The person that has high sensitive will find the different that cannot be viewed by the people with less sensitivity. This condition of course cannot be accepted in the manufacturing industries that need the stability of his production. The industry need to get the same product, every time no matter who is doing the production and QC.
  • Evaluating color by human is strongly influenced by mood and feeling.
Many research proof that the color can affect the person's mood and feelings. This fact is also work at the opposite way; how human see the color is highly influenced by one’s mood and feeling. It means that the color evaluating by humans tend to give nonstandard result.
  • The color looked is highly influenced by the environmental conditions.
Most of object does not have his own light, but reflect the rays that come to him. The visible color from an object actually is the result of light with certain wavelengths reflected by the object, while the other wavelength is absorbed by the object. The lights that come to the object will highly determine the color of the object. The same object can have different colors when it is viewed in the different place. The color of the object will changes if the object is viewed in the inside room or outside room. The color variation is also found if we check the color in different time such as: in the morning, afternoon or evening, when the day light, or at rainy day.

From the explanation above we can see that checking color manually could result to the inaccurate and unstable result. To help people to check and view color, then the tooling industry has created the device to measure and observe the color that is called as spectrometer. .The device is used to help people to check and measure the color. The device will give some number as the quantitative result for the measured object. As machine spectrometer also give the accurate, consistent and standardize result.

How to use spectrometer.

Spectrometer measure the color in three dimensional aspects that is shown in the three perpendicular axis; L (lightness), a (degree of red and green color) and b (degree yellow and purple color). See the picture below:


L axis (Lightness) is the color strength. It is represented in the vertical axis. It is shown by a number ranging from 0 as the black color to + 100 as the white to color.

A axis is the red and green color. It is represented in the horizontal axis. It is started from -100 number as the green color to the + 100 as the red color.

B is the yellow and purple color. It represented by another horizontal axis. Started with -100 as the blue  to + 100 for the yellow color.


The spectrometer measure color of the object and resulted to three numbers that expresses the degree of the color. From the figures we can determine the color of the object being measured. For example from the measurement we got the result as follow: L  (Lightness) : 10, a (redness) :20 and b (yellowness) : -25. From the number we can determine that the color is light red and blue brown,

Spectrometer can also be used to compare the color of the product with the standard. When we use the spectrometer to compare two or more color panel, then he will give three numbers as the deviation result.