Final answer:
The stylist should take into account the client's previous chemical treatments to determine the appropriate solution and processing time for a successful permanent wave. Understanding the hair's chemical history and condition is crucial for achieving desired curl results.
Step-by-step explanation:
When a stylist is preparing to perform a permanent waving chemical service on a client with straight, coarse hair, and the previous results were not satisfactory, the stylist should consider the client's previous chemical treatments. This is because the hair's capacity to curl can be influenced by how it has reacted to past treatments and its current condition. Before performing the service again, the stylist needs to assess the hair's elasticity, porosity, and history of chemical processes to choose the appropriate perm formula and processing time.
Permanent waving disrupts and reforms the disulfide bonds in hair strands using chemicals, typically ammonium thioglycolate. Understanding the hair's history with chemicals is essential because if the hair has been previously treated, especially with permanent hair color, it might have altered the structure of the hair, affecting how it responds to the perm solution.
Hair that did not curl as intended in the previous perm could indicate that the hair is resistant to the waving process or that it was not processed correctly. Adjusting the strength of the perm solution or the processing time, or using different wrapping techniques, may yield better results. The stylist should also ensure the client understands proper aftercare to maintain the new style.