Cold perm and digital perm 

Digital perms are popular in East Asia, particularly in South Korea and Japan, and have gained popularity in other parts of the world for their ability to create long-lasting, natural-looking waves.

Here's a comparison of their differences:

Cold Perm: for Short hair, People who want volume at the roots 

• • No heat is used; the solution itself causes the hair to form curls.

  • Produces tighter, more uniform curls.

  • Curls tend to be more defined when the hair is wet and requires more maintenance to keep curls looking defined and frizz-free.

  • Styling products like mousse or wax may be needed to maintain curl shape.

  • Suitable for short hair style or good for people who want a more classic curly hairstyle.

Digital Perm: for Thin or soft stragiht hair 

• • Uses a combination of perm solution and heat.

  • The rods are connected to a digital machine that controls the temperature and duration of the heat applied.

• • Creates softer, more natural-looking waves or curls.

  • Waves or curls tend to look more natural and relaxed, especially when the hair is dry.

• • Best suited for people with medium to long hair.

  • Ideal for those looking for loose, natural waves or curls.

  • May not be as effective on short hair.