Grapheme Frequency and Color Luminance in Grapheme-Color Synaesthesia.

The authors reflect on studies regarding the association of specific colors with specific letters and digits in synaesthesia. They said that a relation exists between grapheme frequency and the luminance and saturation of synaesthetic color experiences. It shows that only those who completed the assessment have high degree of consistency in their grapheme-color matches. The studies suggest the possibility that the quality of synaesthetic colors may be related to grapheme learning.