Understanding ink deficiencies. Yellow- best and purest pigment on the market. Major impurity- magenta, minor yellow. Color being impure- pigment can still be chemically pure individual. Process inks- vary from one to other manufacturer.
Limited illumination restricts cones from sensing color.
Every individual perceives color differently- based on differences in 6 million cones in eye. Cones- selective receptors of red, green or blue light or chromatic color. Human brain is not capable of remembering color or tone on absolute basis. Fatigue influences next color to be viewed. Each individual recalls those.