A study published in 2017 by the University of Pennsylvania looked into the effects of different colors of light in comparison to normal household white light, specifically in regards to biomarkers related to stress. The resulting findings suggested blue light with a wavelength of 471 nano-meters both sped the time to recover from stressful situations and consistently helped to maintain minimum stress levels.
The set up to the experiment began by instructing the test subjects to preform stressful tasks in a classroom/work environment. The subjects were then moved to "relaxation rooms" with lighting of specific coloring. During this time the subjects were monitored via EEG and ECG sensors. While this test was only an initial sampling, it showed an improvement in stress reduction in 83% of the test subjects.
While the test was done using 471 nano-meter light, I have yet to find records of a replication and any additional data gathered from that so it is possible the effect could be seen in the range of light between blue and violet (400-500 nm). It is also important to note that these studies looked at times of exposure under an hour To account for the sleep disturbance caused by long exposure to blue light, it may be important to allow for a wider variance in color transitioning in future iterations.