What is practical lighting problems?
Think carefully what your lighting should actually do for your subject, other than simply allow convenient exposure settings. Perhaps it must emphasize the form and surface textures of a building, or a small product in the studio. It might heighten features in a dramatic character portrait, or be kind to an ageing person’s wrinkles. Your lighting will often be the best way to emphasize one element and suppress others, or reveal extreme detail throughout. It can ‘set the scene’ in terms of mood and atmosphere, and alter your composition by attracting the eye to a certain point of the image or simply solve a technical problem such as excessive contrast in an existing light situation.
What is Existing light?
Learn to observe ‘existing light’, noticing what is causing the lighting effect you see, and how this will reproduce in a photograph. For example, look up from this book for a moment and observe how your own surroundings are lit. Is it hard illumination or soft? Even or uneven? Which areas are picked out by lighting direction and which suppressed? Are any textures or forms emphasized? Try narrowing your eyes and looking through your eyelashes – this makes shadows seem darker and contrast greater, a good guide to their appearance on a final print.
What is Daylight?
The lighting quality of daylight ranges from intensely hard (direct sun in clear atmosphere conditions) to extremely soft (totally clouded sky in an open environment). Colour varies from an 18,000 K intense blue when your subject is in shadow and only lit from blue sky, to an orangey 3000 K around dawn or dusk; think of those popular sunset shots bathed in warm orange light. (Strictly ‘daylight’ colour film is balanced to give correct colour reproduction at 5500 K, this being a mixture of direct noon sun plus some skylight.) We barely notice these differences as our eyes and brains constantly compensate for them. You can see this most clearly by standing in an ordinary tungsten-lit room at dusk.
Everything looks natural, but if you glance out of the window the world outside looks very blue indeed. If you step outside at this point your eyes quickly adjust to the prevailing light and looking back through the window from outside shows a very orange-looking interior. Through practice you will soon become used to understanding how light will affect your colour photographs, how flash, tungsten and daylight are linked through colour temperature measured in kelvin. Colour daylight film and flash units are balanced at 5500 K to match direct noon sun and tungsten film and lights are balanced to 3200 K that matches the orangey tone of dawn or dust.
The direction of daylight changes throughout the day as the sun tracks in an arc from east to west, being at its highest point at noon. This point is highest in summer and truly overhead only at the equator. Considered use of daylight for subject matter such as architecture and landscapes calls for planning, patience and the luck of getting all the aspects you need together at one time.
The varied character of natural daylight is often an important feature in pictures shot outdoors: the orange tint of a setting sun can add to the impression of an evening atmosphere if it is a realistic impression that you want to achieve.
What is Supplementary daylight?
Often when you are working with existing light you will need to modify it in some way. When shooting a black and white portrait outdoors, you may find direct sunlight too harsh and contrasty, but the light changes completely if you move your subject into the shadow of a building. However, this can give an unacceptable blue cast with colour photography, so it may be better to remain in sunlight but work near a white wall, or have a reflector board or even just a newspaper to return light to the shadow side. Another way to soften harsh shadows with close subjects such as portraits is to use a diffused flashgun on the camera. Since the latter is likely to be a battery-operated flash unit you cannot see the effect created unless you are using a digital camera or shooting instant picture material, and results have to be worked out by careful calculation of exposure.
Supplementary light is often necessary when you shoot an architectural interior using existing daylight. There may be excessive contrast between views through and areas near windows, and the other parts of a room. You can solve this by bouncing a powerful light source off a ceiling or wall not actually included in the picture, to raise shadow-area illumination to a level where detail just records at the exposure given for brighter parts.
This artificial light source might be portable QI lamps or a flash unit. If you are shooting in colour, ensure any tungsten supplementary lighting is filtered to match the daylight, and be careful not to bounce off tinted surfaces such as coloured walls. Sometimes a dimly lit interior can be ‘painted with light’ to reduce contrast, by moving a lamp in a wide arc over the subject during a long exposure.