How Do You Make A Double 40 Developer?
To make a double 40 developer, you need to combine equal parts of a 20-volume developer and a 30-volume developer. This will create a solution that has a strength of 40-volume developer. Make sure to mix the developers thoroughly before use. It’s important to note that using a higher volume developer can result in higher levels of damage and possible breakage, so it’s important to use caution when deciding on the strength of developer to use.