Being a noob and non-techie, I wouldn't know that myself. I just sat all morning and converted the colors of various images to a bluer shade, using MS Office Picture Manager. The values I gave to the three parameters in purple images were as follows:

1) Amount : 65
2) Hue : -180
3) Saturation: 0 (unchanged)

Though not perfect, I like the new theme colors. Screenshots are attached below. If you like it, please guide me how to get the hexadec values and I'll post them here.

One help that I need is how to change the color of highlight and painted text in virtual keyboard. That still remains purple.