When was the acid wave invented?

The invention of the acid wave can be traced back to the 1970s. This type of perm revolutionized hair styling practices at the time because it utilized a milder formula compared to the traditional alkaline perms, making it suitable for a wider range of hair types, particularly for chemically treated or fragile hair. The acid wave is known for producing softer, more natural curls and waves, which were favored in the hairstyling trends of that era. This innovation allowed hairstylists to cater to diverse client needs while maintaining the integrity of the hair. Thus, the correct answer reflects the significant advancements in hair design that began during this decade.