The ways that light is changed by the sky are many. What makes skylight different from direct light is that skylight comes from many if not all directions. It is what makes it possible to still see objects that are in the shade. The Earth's atmosphere also filters and refracts light. Blues are filtered out first and that's why the sky is blue. What makes sunsets and sunrises so warm in color are because reds tend to persist through clear atmosphere without being difused. Overcast skys tend to be bluish in color. These are the two opposite poles of the spectrum in typical temperature-based white lighting. It is what our "white LED modules" strive to simulate. In rare weather conditions associated with tornados, skylight often has a strange greenish hue. It takes more than normal color temperature-based emitters to provide this effect. It is interesting that, in marine environments, the opposite of this trend is true. Reds are removed first from the water column while blues and purples persist the farthest into the deep.
Our systems simulate skylight in a chroma key studio by placing our LED modules overhead in the main stage area. These modules distribute the light over a broad area over the actors' heads. To diffuse the light even more, we recommend facing the LED modules upward so that their light reflects off the ceiling. We have painted the ceiling over the stage area in our studio with a high-refective white paint. Those or you who do not wish to do this can get more light out of the modules by facing them downward. But the light will not be as diffuse and your actors will see the glare of the individual LEDs which are very bright. Reflective surfaces on objects in the live action area of the stage (such a sun glasses) will reflect the skylight as points of light and this should generally be avoided. One could cover the LED modules with difusers but one can gain the same effect by facing the modules upwards and using the studio ceiling to difuse the skylight. Simulating the artificial lighting of indoors is pretty straight-forward and doesn't pose much of a challenge.