Depending on the individual's hair washing routine, and the amount of food coloring used to dye the hair, food coloring can last from as little as one week on to a couple of months according to allwomenstalk.com. Using a concoction made of food coloring and white conditioner or clear gel will help to distribute the color more evenly, making it last longer.
Many people want a temporary solution for dying their hair different colors. Food coloring has been a popular inexpensive method that has been used for years. For the best results, make sure to dye the hair when it is dry. This will help the color stay in the hair for longer processing.
For lighter colored hair, leaving the solution in your hair for 30 minutes will provide the best results. Those with darker hair may need to leave the coloring in for as long as 3 hours.
Waiting to wash for an appropriate length of time after dying will also assist the coloring in lasting longer. It is advised to wait at least 24 hours before washing the hair with shampoo.