The idea behind the article is clever. Unfortunately the technique must have been created by a man as no woman would have suggested the results as looking natural.

Except for some Asians, real hair has highlights and dark tones. The results of the technique in the article creates a new hair color that is much too monochromatic. Why do you think many women pay hundreds of dollars every 4 or 5 weeks to have a hair color professional do their coloring? So the hair has a nice variety of tones.

Look at the first illustration in the article. The original dirty blonde color has a nice range of light blonde, ash blonde, and dark blonde hair. But the two "dye jobs" in the illustration are a rather flat monochromatic brunette and redhead. Does she or doesn't she? Everybody, not just her hairdresser, knows for sure.

Even the last illustration shows this problem. Although its hard to see all the tones in the original brunette color, the three results look more like a doll's hair than human.

How would I colorize hair? Strand by strand using different hues on a paintbrush set to Hue or Colorize. That is the closest to my own hairdresser's treatment of highlights.