How come chemical vendors almost always emphasize that their oxides 
     are converted/reduced? Is the reduction process a relatively new 
     technology?
     
     If so, before the reduction process is available, how did PCB shops 
     prevent pink ring formation?
     
     The reason I ask is that, since there is a "pink ring" solution - 
     reduction of oxide, whenever there is pink ring occurence, one would 
     point at the reduction process by first instinct, forgiving other 
     possible pink ring causes. We once faced an extremely painful pink 
     ring crisis, and were able to end it by improving the oxide reduction 
     process. However, during the crisis, I found out that I can separate 
     the oxide-coated copper from the prepreg by using a knife. It was that 
     easy even without thermal-shocking the board. And after the separation 
     there was not even a bit of oxide seen on the prepreg side. I 
     considered this as an evidence of poor lamination.
        Although we solve the pink ring by oxide reduction, I think may be 
     we might not have the problem in the first place if the lamination is 
     in perfect contition.

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