Colored pencils Color effect – Sunlight shining through stained glass onto carpet (Nasir ol Molk Mosque located in Shiraz, Iran) Colors can appear different depending on their surrounding colors and shapes. The two small squares have exactly the same color, but the right one looks slightly darker, the Chubb illusion. Color (American English), or colour (Commonwealth English), is the characteristic of human visual perception described through color categories, with names such as red, orange, yellow, green, blue, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the visible spectrum. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc.