I can't imagine why you would want to do that, but it just looks like a bluish bias level was added to everything. Note that the blacks are NOT black. It looks like in this case about (0, .18, .34) was added to the black level.

Here is the original central area of your first picture:

I found the darkest area and subtracted off the black level:

The blacks are now black, and as you can see the remaining colors look plausible considering someone greatly cranked up the contrast originally, probably in part to compensate for the blue wash.

Some of the detail in the dark areas can be made more apparent with a non-linear brightening:

Unfortunately this is now amplifying small differences in the darkest area of the original, so we are getting some noise and color fringing. A little bit of a greenish cast appears, particularly in the dark areas. Some of this is due to working with the limited color resolution of the original where much information was already lost.

In any case, since I was able to reverse most of the process, it should be pretty clear that the effect was mostly fudging the black level to be bluish.