The article explores the impact of colour lightness on the perception of product adequacy for consumers in two demographic categories (children versus adults). A pretest preceding the main study identified three demographically neutral objects to be coloured in two lightness variants: light and dark. Subsequently, a series of three studies involving a total of 474 adult participants focused on evaluating a product presented in two colour versions: light and dark, deemed appropriate for children and adults, respectively. The study revealed that light shades of the same colours are considered appropriate for children, while dark shades are perceived as suitable for adults. Thus, the research emphasizes the role of colour lightness in shaping the perception of a product among adult consumers in Poland.