Create a vision board collage portraying the theme of 'Sleep'. The overall style should resonate with key characteristics of the Impressionist era, such as loose brushwork, open composition, emphasis on light in its changing qualities, and ordinary subject matter. The board might include aesthetically pleasing depictions of serene sleeping environments, peaceful bedrooms, gentle nightscapes, quiet nocturnal scenes, and perhaps even individuals in deep slumber, all represented through the impressionist lens. The emphasis should be on the feeling and atmosphere of sleep, rather than on minute details.