There comes a time when every photographer wants to do day for night, Hollywood speak for filming during the day and turning it into night in the editing room.
Photoshop users can do it, too, and there are a lot of ways to accomplish this.
I took pictures of a broken down, abandoned house in Wisconsin, and always during the day, and it always seemed like the perfect photo to play with for this experiment.
Nice, but not scary. So in my first experiment on this photo, I added a layer of black and dialed the opacity down to 75%. YMMV. And then I started adding stuff to it, layer by layer. See if you can spot the additions!
By adding a black layer instead of desaturizing the original, I kept the color of the original picture. I wanted that, because as you can see, I needed to mask it back under the windows where the light pours out.
You did see the lady ghost, right? :) What about the bat? Small kitty, too. :)