What term describes the obvious difference between two colors on the hair shaft?

The term that describes the obvious difference between two colors on the hair shaft is the line of demarcation. This is a crucial concept in hair coloring, particularly when discussing the visible separation that occurs between different color applications. A line of demarcation is often seen when hair is colored, as it denotes where the new growth or previously colored hair begins and ends, highlighting a stark contrast between the two different color shades.

Understanding the concept of a line of demarcation is essential for haircolorists, as it helps in determining how to blend colors effectively and avoid any harsh lines in the transition from one color to another. This knowledge is particularly important during coloring processes, touch-ups, or when correcting color.

The other terms mentioned do not capture this specific concept. The color spectrum refers to the range of colors available, color transition describes the gradual change from one color to another, and a color gradient represents a smooth blending of shades rather than an obvious separation. Recognizing these distinctions can enhance a haircolorist's skills in achieving a desired aesthetic outcome in hair coloring.