Endothermic atmosphere is prepared by reacting a mixture of hydrocarbon gas, typically methane or. propane and air, metered in a proportion such that there is just enough oxygen to form carbon monoxide. and hydrogen without excess carbon dioxide or water vapor.
But for your everyday run-of-the-mill deep conditioner, it should begin to work instantly, and reach maximum capacity at around the 20 or 30 minute mark. If your deep conditioner doesn't work after 30 minutes, it's time to ditch it for one that's more effective.
Let the dye set. How long you should leave it in for will vary by brand, but 30 minutes to an hour is typical. Unlike permanent dyes, which contain harsh chemicals that can damage your hair and skin, there is usually no too long with semi-permanent colors. If you want to leave your work area while the dye sets, put your hair in a shower cap to keep from making a mess.