While you may not be familiar with the term spot color, it may be the more widely used of the two in the sign and screen printing world. This is because the majority of simple signs produced are using self-adhesive vinyl, which is a spot color media.
There isn’t an actual book definition for spot color, but basically it means that the color was pre-manufactured at some point, other than at an actual inkjet digital printing device, such as an inkjet. Some examples of spot colors include a bright pink paint color, a golden yellow screen printing ink, and a sapphire blue vinyl color.
Process color, on the other hand, means the four colors of yellow, black, cyan and magenta are mixed by the printing device in different percentages of dots to create a full range of colors. Inkjet printers produce images using process colors and most often full color magazines and brochures are printed using process colors.
Traditionally, spot colors using vinyl sheets is ideal for sign printing for a number of reasons. First, spot color is a solid color, whereas process color must mix a series of dots to create certain solid colors. Process colors are also unable to create all colors, so spot colors can fill in where process colors are weak. Spot colors can also save on time and materials.
Despite this, digital sign printing using process colors is coming on strong. They can make hundreds of thousands of colors by simply changing the concentration of the four main colors: yellow, black, magenta and cyan. Process colors can be easier to match than spot colors, reproduce images (especially photographs) realistically, and combine to make new colors.
Ideally sign makers should have printers that use both spot and process colors to create the best looking signs possible.