I recently posted a blog article about the Blue Hour.
One thing I didn't mention in the blog was how subtle warm hues, remnants of the sunset benefit from the contrast against the rich cool tones of the Blue Hour.
I first discovered this in 2008 while photographing the dramatic seascapes of the Tasman peninsula in Tasmania. The light was incredible that day. Heavy clouds and rain had made photography difficult all day until late afternoon when a break opened in the sky, letting in some golden light and a gorgeous rainbow. I shot well into the evening. Even when all the colour had seemingly disappeared, I stuck around to shoot this 5 minute exposure. To my surprise I could see some very obvious pinks in the clouds on my LCD screen. When I looked more closely at the sky, it dawned on me that the colours were there but not noticeable unless one made the effort to specifically look for them. It was one significant step in my quest to understand light.