The primary intermediates are aromatic para compounds , such as 1 , 4 - diaminobenzene or 4 - aminophenol .
Various combinations of primary intermediates and coupler compounds provide a spectrum of shades of hair colors .
The primary intermediates are aromatic para intermediates , such as 1 , 4 - diaminobenzene or 4 - aminophenol .
Various combinations of primary intermediates and coupler compounds provide a spectrum of shades of hair colors .