Blue Hour refers to the time after the sun goes below the horizon and the sky goes into deep blue for a while.
To find out the best period to be shooting Blue Hour, I dial in my intended subject into Sun Surveyor to confirm sun direction (which believe it or not is very important when it comes to Blue Hour photography) or you could use the Blue Hour Site (this only gives you times and not sun angles). They then spit out a rough period when it considers is the best chance to capture Blue Hour. Problem is, this is a little vague for what I aim to achieve. That is because:
- it is still to light;
- it is now too dark; and/or
- the angle of incidence to the subject in relation to the recently set sun.
Let me explain these three concepts a little bit better.
To Light:- Fairly obvious, I know, but when it is to light the blue is quite washed out and boring.
To Dark:- The sky becomes black and in my humble opinion, just doesn't work well with architecture.
Angle of Incidence:- This is very important to know where the sun has set. If you face towards or directly opposite the set sun, you achieve the optimal angle of incidence and the result is a nice even blue. Start to turn off angle from the sun (Say 10º – 80º either right or left of centre), then you are going to get a gradient of colour, which is not that pleasing to the eye.
So what does this mean? Let me start with yesterdays time (29 Aug 2015) suggested by Sun Surveyor as the period for Blue Hour. It recommends that between 1752 and 1826 is the period of Blue Hour. You will note that this is actually 34 minutes, which kills the theory of Blue Hour. If you look at the first photo below, it was captured at 1810, which is roughly the centre of the period of time suggested. A day or two before and you can see the Kingston Foreshore Apartments were shot only 2 minutes later.
Now to the morning photos.The Royal Australian Mint is a fine example of the sky being too light, but the issue I had was those coloured lights on the façade of the building were changing colours at an interval of approximately 2 seconds, so I had to match my shutter speed, aperture and the sky, so it was all balanced.
Next is the Albert Hall. You can see that the sky is just too dark. This photo was a compromised photo, as my intended target was the Hyatt Hotel, below it. Check out the times, only 7 minutes between shots. In those 7 minutes I walked about 100 metres and worked out my location and set the tripod and camera up. Such a huge difference for only a few minutes. These last two images, is why I ponder if it is actually Blue Minutes instead of Blue Hour.