Spot color Spot color In offset printing, a spot color or solid color is any color generated by an ink (pure or mixed) that is printed using a "single run", whereas a process color is produced by printing a series of dots of different colors. The widespread offset-printing process is composed of the four spot colors cyan, magenta, yellow, and key (black) commonly referred to as CMYK. More advanced processes involve the use of six spot colors (hexachromatic process), which add orange and green to the process (termed CMYKOG). The two additional spot colors are added to compensate for the ineffective reproduction
C-41 process not is a subject of some debate. C-41 film consists of an acetate or polyester film base, onto which multiple emulsions are coated. Each layer is only sensitive to a certain color of visible light. In the classic illustrative example, there are three emulsions: one is red sensitive, another is green sensitive, and the top is blue-sensitive. Beneath the blue layer is a yellow filter, composed of dyes or colloidal silver. All silver-based photographic emulsions have some sensitivity to blue light, regardless of what other colors they may be sensitized for. This filter layer serves to remove the blue light,