## 1 Introduction  
The perceived color of interior furnishing and apparel products is a very important component of interior design and visual merchandising [1, 2]. Color may positively influence consumers' attention and draw them toward products. A possible effect of increased attention due to color can positively influence consumers' purchasing decisions and increase the sale of textile products. Notably, the color of a textile product largely depends upon the illuminants used in the retail stores, illuminants available to the consumers while using the product, and features of the product, such as its constructional structures and surface attributes (pile height, gauge, stitch rate, carpet density) [2, 3, 4]. Prior research has found that a few illuminants, namely Cool White Fluorescent (CWF) and Incandescent (A), were predominantly used by visual merchandisers and/or interior designers in retail stores and homes [5, 6, 7]. However, the recent need to reduce operating costs (lighting is one of the biggest expenses in the U.S. retail stores) and energy consumption (lighting accounts for 50% of the total energy used in U.S. retail buildings) in retail stores have also led to the use of other illuminants such as simulated Daylight Fluorescent (D65), by interior designers and visual merchandisers [5, 6, 8]. Additionally,after purchasing textile products from retail stores, consumers may view the products under incandescent (A), CWF (F02), and noon daylight (D65) illuminants, while traveling, shopping, at home, at work, or outside [9; 10; 11]. Altogether, it is obvious that the color appearance of textile products would vary at different times of the day depending upon the types of illuminants to which products are exposed [11; 12]. Considering the above situations, textile researchers and manufacturers should measure the color appearance of textile products under different illuminants commonly used by interior designers and visual merchandisers in retail stores as well as under illuminants to which products are exposed during routine use after installation. However, many textile researchers and manufacturers only measure the color appearance of products in laboratory conditions under a D65 illuminant potentially due to their limited access to different illuminants or shortages of time and money for lab testing [13; 14; 15]. The measurement of the color appearance of textile products by the manufacturers under only one illuminant could lead to misleading information for interior designers and visual merchandisers, as well as ultimate dissatisfaction of consumers when viewing color variations in the textile products under other illuminants [16; 17; 18]. Consumers' dissatisfaction may eventually lead to both loss of sales and patronage for retailers. Hence, there is an immediate need to scientifically study the color appearance of textile products under different illuminants and to provide a time- and cost-efficient mechanism (i.e., a model) to predict the apparent color. This research agenda could help manufacturers, interior designers, and merchandisers to accurately and conveniently predict the color appearance of textile products and to provide detailed color information for products under varied illuminants prior to consumer evaluation and purchases. Fairly recently, [PERSON] and [PERSON] [9] scientifically studied the color appearance of textile products under three different illuminants--I, D65, and CWF. They used experimental and statistical techniques to characterize the textile products and found that perceived color appearance significantly varies with the type of illuminants. However, [PERSON] and [PERSON]'s research focused on apparel textile products only. They did not explore interior furnishing textile products and the effects of textile product features on the color appearance. Additionally, they only statistically correlated the color appearance of textile products with different types of illuminants.