In late February, an innocent question raised by Grace Johnston from Scotland as to what color a striped lace dress her mother wore to her wedding on Tumblr went viral on the Internet. Celebrities and public were equally divided as to whether the dress was blue and black or white and gold, and the heated debate went on well into mid-March. Since the incident, there has been many theories ranging from genetics, optical illusion, visual perception, and poor lighting to explain the phenomemnon.
Experts are saying the yellow lighting and reflected light caused the dress to be perceived as gold and white, and lack of lighting cues to indicate whether the dress was in a shadow caused the brain to misinterpret the colors. Some say this is a visual phenomenon. Others even turned to genetics or the number of rods/cones in people’s eyes as an explanation.
There are many possible reasons why the color of this dress appears different to different individuals. For starters, visual perception of color varies from person to person. Also, the colors that we see are those that are reflected off the dress. Hence, if a light source has a spectrum that is missing colors or has very little content of certain colors (like blue), these will not be reflected off the dress, causing a different visual perception of the colors of the dress. Furthermore, if the light source is very bright, we lose our ability to distinguish colors due to glare.
What kind of lighting or color temperature should retailers use to avoid color distortion? What is the recommended color temperature for different kinds of retailers, grocery markets, fashion and clothing outlets, restaurants, jewelry and others? Why should retailers be concerned that they get the color temperature right? Does lighting angle, and the way the luminaire is installed also have an impact on the perceived colors?
Comment 1: This is a difficult question to answer because it depends on the retail establishment, the type of merchandise being sold, the image the store is trying to project, etc. To minimize color distortion you need a light source with a high quality spectrum –one that contains all necessary colors of light in the right amounts. Measures of the quality of light include CRI, or the equivalent, and gamut area index. High quality light sources can be found at many CCT’s.
Comment 2: A store owner should be thoughtful in picking a color temperature to ensure their product is presented in the best possible light, but also create an environment that is comfortable and productive for employees. Select a color point that is focused on primary business objectives. First, decide if you want to optimize for efficacy ($/per lumen) or optimize for color quality. If you are more concerned about energy savings (via efficacy) you will want to select a cooler temperature CCT and lower CRI. If you are looking to optimize color quality, you would want to select a higher CRI and likely a warmer color point.
It is difficult to select a specific CCT/CRI for retailers in general, because it should be driven by their specific lighting objectives. The color temperature used in an Apple store is going to be very different than the light going into a Louis Vuitton store and the light we used at Green Apple Books. The Apple store is going to use a bright, punchy, cool to neutral white point (i.e. 4000K CCT with a high CRI and high GAI) to achieve a specific store/brand aesthetic. A Louis Vuitton store would likely use a warmer color point (i.e. 2700K-3000K with a high CRI and GAI) to showcase its colorful handbags and create a cozy, warm, luxurious shopping experience.
Remark: We focus on LED Lighting, and our products include T8 LED Tube Light, LED Panel Light, LED High Bay Light, etc.