I think its awesome to have a B&W image and leave those color details. Not only its the contrast eye-catching but it gives the image more life that if it would be plain B&W or plain color Arquitectural photos are always cool, but I find that putting people in them helps somehow. Maybe its because I prefer the idea of buildings that serve for someone, or maybe its how it helps see the scale of it. awesome photo
That particular shade of orange is more indicative of Chinese influence. Which dates it to the Heian period -when Japan was heavily influenced by China. Koya is a center of Shingon Buddhism which was a very old form of Buddhism in Japan's history -one of many varied imported forms (didn't really stick) that was aimed more at the upper classes. At this time, power and influence were still in the high courts as opposed to with the warrior class. Been a long time since I studied, but I believe that's all correct.
Definitely true that different colored gates will have different historical/religious significance. You wouldn't find such flashy gates in a Zen Monastery, for example, because the aesthetic there leans towards austerity, asceticism, and more weathered earthy tones. The emphasis being on transience rather than glitz and opulence. In the case of Shingon Buddhism, rich patrons naturally wanted a rich and visually elaborate religion. Heian is old school.
Do you have examples of white gates? That stumps me a bit.
I'm totally at a loss on that one. My guess is that it's a Shinto thing. Perhaps painted white to match the cherry blossoms? Why not?
The color white, in Japan, is traditionally associated with death. (Black for weddings, white for funerals). Entrance to cemetery maybe? I'm sure it can have other significance tho. Maybe even if you asked locals you'd get different answers... I wanna know now too!