Before I dive in - just wanted to say thank you for an excellent plugin.
Discovered something which may be useful to others and is possibly an issue with browser rendering of translate3d in certain circumstances (haven't dived in too deep....)
When there is an element layer (1) positioned above the parallax wrapper layer (2), they are siblings, and layer 1 has a higher z-index then on a Safari that supports translate3d then layer 1's text color dims.
I haven't tested to see whether other attributes like background color etc.. are affected by this.
Seen on Safari 7.1
Simple solution is to disable translate3d with the useTransform option.