Let the bowl sit in room temperature as it releases the dye. Make certain that the plastic wrap is tightly covered to quicken the process. If you do not have time to wait overnight, put the henna in a closed pot over a stove for 1-2 hours. Take the temperature of the henna and make sure it's around 90°F (or 32°C). Any hotter, and your henna may not have ideal consistency.If you are using indigo henna dye, use it after mixing. Indigo henna has a shorter oxidation time.
Dye release will occur best in room temperature. Do not place the henna in the refrigerator or freezer until after it has exhibited dye release.
 You will be able to spot dye release by the surface. Your henna should be a dark brown color (or black, if using indigo dye) and have liquid pooling at the top. You can check the surface by pulling back the top layer with a spoon. If the top layer is darker than the bottom, your henna is ready to use.

To test for dye release, put your paste in a plastic baggie. Put the baggie on top of a white paper towel. Dye molecules are small enough that they will slip through the plastic. If your paper towel turns slightly orange after a few minutes, your henna is exhibiting dye release., Before you apply the mixture to your hair, put a small amount of henna paste on a spoon. Remove some of your hair from your hairbrush, and let the henna sit on the hair for several hours. After the henna has dyed the hair sample, decide whether the color is ideal for you. If not, prepare a new mixture., Unless you are using indigo henna (which lasts for a shorter amount of time), your henna will last in the refrigerator for three or four days. If you need it to last longer, you can freeze it. Frozen henna can last up to several months with the same freshness as newly-mixed henna.Keep the henna covered with plastic wrap while in the fridge or freezer to avoid drying your henna out.
Let the henna paste sit overnight.
Check for dye release.
Test the color before you dye your hair.
Use your henna within three to four days.
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