Ultramarine blue

How Ultramarine blue behaves on a wall

RAL Colors publishes a light reflectance value of 7.4 for this shade. At LRV 7.4 this is a deep shade: it returns under an eighth of the light that reaches it, so a room painted in it leans on lamps rather than daylight. Over a pale base it usually takes an extra coat before the colour stops looking patchy. For trim that reads as a clear edge rather than a smudge, aim about 30 LRV points away — roughly LRV 37 and up. With 122 points between its strongest and weakest channel it holds a readable blue cast, so it will not flatten into a neutral once it is on four walls. Order by the code, not the name, and put a test patch on the wall before you commit — a screen cannot show you how this shade behaves in your own light.