In iOS7 a translucent UIToolbar or UINavigationBar will now blur the content behind it. The bar’s color can still be set (now with the -setBarTintColor: compared to the previous -setTintColor:), however the UIColor you set is not the same color that will be displayed on screen. Instead, iOS will adjust your RGB values a bit and use those as the color.
The other week I compiled a calculator to determine what bar tint color to set a UINavigationBar to if you want the blur effect on iOS 7. This works well, but only if your RGB values are >= 102 – because Apple adjusts the RGB you set the bar to.
Lately I’ve been experimenting with darker colors, those with RGB values under 102. There is a work around, however it requires some tricks.