Offset printing is also CMYK + White and may have some variations in the form of ghosting, usually in larger areas. Creating gradations on purpose or adding slight textures are great solutions for getting good, solid colors with offset printing.
Printing process that use special spot colors or Pantone Matching System (PMS) colors (such as Silkscreen) do not have issues with solid colors when using 100% of the defined color. When used with solid colors in any size area, Silkscreen creates an even, glossy print. However, when used in halftones, percentages, or when printing in processed bitmap images, Silkscreen will print with a dot pattern. The best thing to remember when printing large areas of solid colors is that Silkscreen printing is ideal, including vector artwork to specific spot or Pantone colors.
Still have concerns with your solid colors? Are you in need of artwork recommendations? Contact your account representative or one of our graphic designers at 1.877.992.3766.