After just a few days I updated ColorPicker and added a detection of RAL colors to the full version and a German localization.
Detecting colors of a color palette like RAL colors is always an approximation. Furthermore the detected RGB code depends on the image taken by the iPhone’s camera. As the camera does some “optimization” like adjusting the brightness the App can rely on that adjusted colors only. To get the best results use natural daylight conditions when using ColorPicker.
But long story short – check out ColorPicker on the App Store: