The assumption made in my previous post about Photoshop's cooling filters was that they simulate blue light (either predawn or post sunset) streaming into the bedroom from an outside window, and illuminating the entire scene. However, what if the window was smaller, and illuminated only part of the scene? Here is another example from the series with Andrelica, where the Cooling Filter (80) has been restricted to the bottom half of the image:
This was easily accomplished by drawing a black-to-transparent linear gradient over the white mask of the cooling filter layer. Not only does this easy technique provide an interesting variation to boudoir images, but also keeps the tonality of the skin color of her upper body closer to normal.