How to Photograph Blue Hour: City Lights and Reflections

Some of the most interesting conditions for photography appear when the sun is already below the horizon but the sky has not yet become dark. Cool blue tones meet the warm light of street lamps, windows and illuminated façades. The city begins to look different from daytime while retaining more detail than in the middle of the night.

This is blue hour. In this article, I focus primarily on photographing architecture, bridges and city skylines. Landscapes and reflections in water complement this subject.

When is blue hour?

Blue hour occurs before sunrise and after sunset. However, it does not describe a precise, consistently identical period of time. Despite its name, it does not have to last sixty minutes. Its duration and appearance depend on the season, latitude, cloud cover and atmospheric clarity.

It should not be equated with the whole of civil twilight. For a photographer, what matters most is the moment when the sky has a distinct blue hue and the brightness of natural light works well with the city’s lighting.

In the evening, arrive before sunset. Choose your composition and check when the illuminations switch on. In the morning, the changes happen in reverse: the sky brightens, and the lights may switch off before you achieve the effect you want.

Why does the city look so good then?

After nightfall, bright windows and street lamps contrast strongly with their dark surroundings. During blue hour, the sky still illuminates the scene. It is easier to retain clearly defined building forms and façade details without excessively brightening the shadows.

Another advantage is colour contrast. A deep blue sky provides a natural backdrop for warm lights. Waterfronts, bridges, squares, and historic or modern buildings with interesting illumination work particularly well.

Look for a specific subject. The colour of the sky alone cannot replace composition: the line of a street, the rhythm of windows or the arch of a bridge should guide the eye through the frame.

Camera settings — where to start?

The settings below are starting points for a stationary scene photographed from a tripod, not a ready-made recipe for every shot.

The light fades quickly. Check your exposure every few shots. A setting that worked five minutes earlier may already produce an image that is too dark. Set stabilisation for tripod use according to the instructions for your particular camera and lens.

Focusing on architecture

Focus on a clear, high-contrast edge of a building. Check it using a magnified preview. If autofocus starts hunting or jumping between subjects, switch to manual focus.

Do not automatically set the lens to infinity. If the frame includes a close foreground, check its sharpness separately from the distant buildings. The depth of field you need depends on focal length, aperture and focusing distance.

Protect highlights, but do not fear shadows

Detail is easiest to lose in illuminated façades, signs and bright windows. Use the histogram and highlight warnings. Viewed in dark surroundings, the camera screen alone can give a much brighter impression than the recorded photograph.

A small amount of clipping in the light source itself may be unavoidable. Preserving the texture of the illuminated building is more important. Do not brighten the entire scene just to make every shadow light.

If the contrast exceeds what a single shot can capture, use bracketing, for example three photographs at −2 EV, 0 EV and +2 EV. Keep ISO and aperture fixed and change the shutter speed. When blending exposures, check whether moving cars, people or water have caused ghosting.

White balance — blue without overdoing it

Automatic white balance can change the colours between successive photographs, especially as artificial light becomes more dominant. A fixed colour temperature makes it easier to compare shots taken a few minutes apart.

Lowering the Kelvin setting makes the image cooler, but does not necessarily improve it. Overly blue façades and almost white street lamps can make the scene look unnatural. Preserve the relationship between the cool sky and the warmer city lights.

Under mixed lighting, a single white balance setting will not neutralise every light source. With RAW, you can refine the colour later, but you cannot recover detail in completely clipped highlights.

Light trails and reflections in water

A few seconds of exposure can turn moving cars into lines that lead through the photograph. Start with 2–5 seconds, for example, and check the result. The length of the trails also depends on the vehicles’ speed, distance and direction of movement.

By the water, a long exposure can simplify the surface of a river or bay and stretch out reflected lights. A shorter exposure preserves more wave texture. Do not choose a long exposure automatically — compare both versions.

A tripod will not freeze a moving boat or swaying branches. If their sharpness matters, use a faster shutter speed and accept a higher ISO. Place your equipment on stable ground, away from traffic and the edge of the waterfront.

Blue hour beyond the city

Cool light also works well by the sea, beside a lake and in the mountains. Instead of illuminations, silhouettes, the shoreline and subtle tonal transitions can take the leading role.

Pay attention to the foreground: a pier, rocks or a shore leading into the frame. Without city lights, the scene may be more subdued — there is no need to artificially increase saturation to preserve its mood.

A simple exercise: one frame, three moments

Choose a skyline with illuminated buildings and take a series from the same position: just after sunset, with a distinctly blue sky, and after nightfall. Keep the composition and white balance fixed, but adjust the exposure as the light changes.

Compare the clarity of the architecture, the intensity of the illuminations and the detail in the shadows. This makes it easier to recognise the moment when natural and artificial light complement each other best.

The most important thing is not to achieve the darkest possible blue. It is to capture a balance that preserves the city’s sense of space, colour and character.

Read also

• White balance — the colour of light and intention
• Shutter speed — how to depict motion deliberately
• Landscape photography settings for maximum depth of field