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Why R9 is Important for High CRI Lighting?

May. 09, 2022
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What is the color rendering index R9?

R9 is a score that represents how accurately a light source reproduces intense reds.


"Accurate" is defined as similar to daylight or incandescent bulbs, depending on the color temperature. As with every CRI R-value calculation, R9 is calculated by calculating the reflected color from a theoretical object, with the reflectance distribution defined as TCS9.

Zoomable Led Track Lighting

Zoomable Led Track Lighting


The Color Rendering Index R9 is one of 15 pigment colors established by scientists to measure color rendering. The Color Rendering Index (CRI) is a range from 0 to 100% that indicates how accurately a "given" light source will render color compared to natural light. However, the current CRI does not take into account the R9 value. Why is this important to you, the R9 value produces saturated, intense, vibrant reds. Again, you're asking why should I care, as R9 values are prevalent in most skin tones, clothing, and food. This is a key factor for anyone considering an LED retrofit, especially for retailers, restaurants, and grocery stores, just to name a few.


Retail Color Rendering Index R9

If you own or manage a retail store, chances are you sell red clothing. We can also imagine that you have customers trying on red clothing. The lighting you choose for the main floor, dressing rooms, and display areas needs to have a high R9 value to accurately show the true red color. As we mentioned before, most skin tones contain red. Not only do you need to worry about how your red merchandise will be perceived. You also need to consider how it will be perceived by your customers.


Supermarket Lighting

 Supermarket Lighting

Restaurant Color Rendering Index R9

When you go to a restaurant and order from the menu, you order based on dishes that sound good. Once your food comes in, you eat based on what looks good. I bit into a juicy apple the other day. While the apple tasted great, when I looked down at it, I noticed it was turning brown. My appetite disappeared. The same is true for customers who visit your restaurant. A customer orders a rare share and waits patiently for the order to arrive at their table. Only to see (below) the unpleasant brown color. 


No matter how delicious the bet is, they won't enjoy it. Plus, you know that severely limits that customer's chances of returning, and (shudder) they might even give a bad review. This problem could have been avoided altogether. When Powerstar performs an LED retrofit for any restaurant, we make sure our customers understand the benefits of high R9 values. We also provide them with LED options that optimize the customer's perception of your food and facility.


Restaurant Lighting

Restaurant Lighting

Grocery Store Color Rendering Index R9

Grocery stores are another place where how customers perceive visible color affects their buying habits. Meeting departments with lower R9 values for their lighting will see fewer sales. A production department with zero R9 lightings will be empty. Grocery stores without adequate lighting will soon go out of business.


Why is red so important?

Red is a key color for many applications, including photography, textiles, and the reproduction of human skin tones. Many objects that do not look red are actually combinations of colors, including red. For example, skin tone is heavily influenced by the reddening of the blood flowing beneath our skin.


Thus, light that lacks red can make a person look pale, or even green. This can be a problem for medical applications where color appearance is critical to an accurate diagnosis. In other applications such as photography, aesthetic appearance is critical and many times cannot be corrected even in post-production and digital editing. When looking for LEDs with high color quality, be sure to ask about the CRI and its R9 value.

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Shenzhen Powerstar Technology Co., Ltd.
  • Tel.: +86 755 8178 4030
  • Fax: +86 755 8178 4030
  • E-mail: info@pstarled.com
  • Add: Building C, 2nd Mingjinhai Industrial Park, Zhoushi Road, Shiyan Town, Baoan District, Shenzhen, China