sky-HDRi.net offers the possibility to use high quality physically correct sky textures for users of 3D software. HDR method of lighting is getting more popular among 3D-artists, since it has a lots of advantages when using standard light source with common parameters of color data and light power.
Objects of your scene will be given correct light depends on atmosphere of sky texture. If panorama is cloudy then objects and reflections will correspond to that by imitating the atmosphere. To change a mood or time of a day just change HDRi map from sunny day with bright light and clear dark shadows to sunset evening with smooth pinkish-blue shade. See the video tutorial to learn how it works.
That's because panorama is the source of light and reflection. High quality panorama contains rich information about light power and color data. Each pixel of our panorama contains 32-bit information of light and color. It's If the sun has a glow it will reflect physically correctly other part of the sky. For example, opened clear sun will give very brightly light and clear shadows, at the same time covered by a cloud sun will be less bright and shadows will be fuzzy.
All textures have resolution 10000 (or more) pixels width and 32-bit color depth, which save users from further substitution of backgrounds during post-production. However, background pictures for post-editing addition to some sky textures are included.