The production process for Copper Oriental, Pale Tan-skin dolls is more complex than for normal skin and pale skin dolls. Furthermore, their defective rates are higher. 

Ultra-low viscosity polyurethane is a thermosetting polyurethane that produces heat and hardens in a chemically stable state when the monomer and curing agent are mixed at a 1:1 ratio by weight. 

To create darker skin tones like Copper Oriental, Pale Tan-skin, a large amount of urethane coloring agent is added when the monomer and curing agent are mixed. 

However, if not mixed properly, it can lead to marbling. In general, around twenty high-quality dolls can be reproduced from a single silicon mold. 

However, taking into consideration the high defective rates, only around four high-quality Copper Oriental, Pale Tan-skin dolls can be reproduced from a single silicon mold. 

That is why they are sold at higher prices than pale, flesh, and oriental skin dolls.