Perm rods, wrapping and processing

Permanent waving and relaxing is the second-heaviest clinical domain, and the wrap questions are the most mechanical part of it — which makes them the most reliably answerable if you know what each variable actually controls.

What sets the curl size	The diameter of the rod
A concave rod	Tighter curl at the center of the rod than at its ends
Croquignole wrap	Wound from the ends toward the scalp
Spiral wrap	Uniform curl from scalp to ends on long hair
End papers	Control the ends and keep them smooth
Sharp bent ends on a finished perm	The ends were not smoothly enclosed in the papers
Panel width	Governed by the length of the rod
Base section	The portion of the panel measured out for one rod
Tension when winding	Enough to keep the strand smooth, not enough to stretch it
Rods between clients	Cleaned, then immersed in disinfectant

Where the point is lost: When a client asks for a softer, looser wave, the answer is a larger rod diameter — not a shorter processing time and not a milder solution. Those change how completely the wave forms, which is a different thing from how big the curl is, and confusing the two produces an under-processed perm that relaxes out rather than the soft wave she asked for.