Why is the top bar in iOS a different colour to the one I specified?

The bar at the top of the screen in our iOS app (known as the 'Navigation Bar') is translucent. As a result, the colour is partially affected by the colour of the underlying view in the app.

Apple have provided a detailed explanation of the issue with tips for how to tackle the issue in the code. Where they refer to decimal values for red, green and blue, these would need to be converted to a hex code as used within Aiir.