The Sherwin Williams tool says that Let it rain comes close.

One side of the room is in the light and it looks like Mild Blue

Difficult to match a colour from a photo. Remember any area on that wall's colour will change approximately 40,000 times a day. The colour being rather saturated with black depend on light quality, distance from where observed, time of day observed, observer. The most scientific colour system is that of NCS(Natural Colour System) and their colour Atlas provides for an excellent couer shifting method where you can easily sort out your colours. But remember, whatever colour you choose from a colour swatch will NEVER be the same on a wall for reasons mentioned above.

Benjamin Moore has a great tool.

color gallery