When would you use 40 volume cream developer?

A 40 volume cream developer is typically used when you want to achieve a significant lift in hair color, such as going several shades lighter or performing high-lift color processes. It's often employed in professional bleaching services or for creating vibrant, dramatic colors. However, it should be used with caution, as it can cause more damage to the hair compared to lower volume developers. Always consider the condition of the hair and follow up with appropriate aftercare treatments.