What does the term "flat color" most closely refer to in printing?

The term "flat color" in printing most closely refers to colors with no variations in tones. Flat colors are uniform in hue and saturation, meaning they do not possess gradients, shading, or highlights. This characteristic makes flat colors ideal for applications such as screen printing and certain types of graphic design, where a solid color can create a striking visual impact without the complexity introduced by tonal variations.

In contrast, colors with distinct saturation may imply some variation, and colors using gradients incorporate transitions between shades, which move away from the concept of flatness. Textured colors suggest physical surface variations, which also diverges from the definition of flat color, as these textures would introduce depth and complexity contrary to the simplicity of flat colors. Therefore, “colors with no variations in tones” accurately captures the essence of what flat color represents in the printing context.