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.
One of the new effects in iOS7 is blurred content. At WWDC this year they were showing off how to do this with snapshots and image filtering. The downside to that is that it’s a static image and wont change with the content behind the view.