One of the most beautiful parts of the henna process is the progression and demise of the stain.  After leaving the henna paste on 4+ hours, the paste is removed leaving a bright stain of varying tone.  Over the next 24-48 hours the stain darkens to tones of reddish all the way to burgundy.  End stain depends on the location on the body, each batch of henna, and individual body chemistry.