Although hair design books warn that customers should get an allergy test 24 hours before dyeing, almost no hair salons do so. Many just give lip service to the problem by inquiring, "Have you dyed your hair before?"
美髮教科書雖然規定：客人染髮前二十四小時要做皮膚測試，但幾乎沒有一家美容院確實遵照規定，頂多只是口頭詢問：「有沒有染過頭髮？」