In this article we show a simple but important relationship between

the put-call transformation and the put-call symmetry as well as extend

the relationship to also hold for single and double barrier options. These

new barrier transformations give new insight in barrier option valuation.

Using the transformation it is possible to value a barrier put option from

a barrier call option formula and vice versa. Our results also extend the

possibilities for static hedging and closed form valuation for many new

exotic options. The new relationships also make us able to value a double

barrier option in a simple and intuitive way, only using a few single barrier