What type of perm rod gives you a uniform curl?

Choosing a straight perm rod is the best option for achieving a uniform curl because these rods have a consistent diameter from end to end. This uniformity allows for an evenly distributed curl across the entire hair strand, resulting in a cohesive and consistent appearance. When hair is wrapped around straight rods, it creates curls that are similar in size and shape, which is ideal for clients seeking a balanced look.

Other types of perm rods, such as spiral, soft, and concave, generally produce more varied curl patterns. Spiral rods create curls that have a more distinct and elongated look, soft rods may yield a gentle wave rather than a defined curl, and concave rods result in curls that are tighter at the center and looser on the ends, leading to an inconsistency in the curl pattern. Each of these variations serves different styling preferences and outcomes, but they do not provide the uniformity that straight rods do.