Light is the single most important factor of all of photography. It's the effect of light and shade that provides images with realism and expression. As impressionist photographers, we don't necessarily photograph what we see. We attempt to capture the light and its effect on the subject matter. The work done in a painterly and poetic manner enables the viewer to become engaged in the interpretation of the subject and mood.
Light is not difficult to understand, but it does require a conscious effort to observe its effects. We have many terms to describe a light source: hard light, medium light, soft light, side light, back light, warm light, low-key, high-key, etc. Basically, these descriptive terms are referring to one or more of the four basic characteristics of light: colour, contrast, direction, and intensity. When you understand the dynamics of these four qualities and their impact on how we perceive form, colour, space, and atmosphere, there is no limit to your ability to use them creatively.
The way an object is lit will depend on whether the day is bright or overcast. On cloudy days, highlights and shadows will be soft, and edges of these shadows will be blurry. On a sunny day, the highlights will be more intense and shadows sharper. Strong light adds depth and drama to a photograph. Soft light lets you capture subjects in a gentle, quiet moment. The direction of the light source has a profound effect on our perception of it and on how an object in a scene will appear. For example, front lighting doesn't reveal form.
"A picture must possess a real power to generate light, and for a long time now I've been conscious of expressing myself through light, or rather in light."-- Henri Matisse
It makes things look flat, but it is very good when it comes to showing off colour. Back lighting can often look very atmospheric and dramatic; it creates a "rim light" that helps define edges. Side lighting is wonderful for highlighting form and texture. Top lighting can lend an air of mystery. You will notice that the quality of (natural) light changes with weather, and also from season to season. Compare the cool light of winter's day with the warm light of a hot summer afternoon.
Colour is the most subtle characteristic of light, but also its most evocative. The colour of light changes throughout the day from the first pinkish spray at dawn, through the clear white light of midday, to the golden moments of the late afternoon.
Consider the feelings you experience at certain times of day, and that mayhelp you choose the best lighting situation for the mood you want to convey in your images.
Light also has a dramatic effect on our moods and feelings. We feel cheerful and happy on a bright, sunny day and perhaps more contemplative or even a bit sad on a succession of grey, overcast days. Translating these emotions into your photographs takes more than just simply recognising objects or estimating the time of day. Whatever the subject, it is the light that determinates the impact that a photograph has. The type of illumination captured in an image strongly influences its mood, feeling, and emotional quality as well as giving life and meaning to the subject captured.
So before you start creating your photographs, you may wish to ask yourself:
What is the direction of the light? Is it direct light or is it diffused light? What colour is it? Are there any shadows, and if so, do they have a hard or soft edge? Is the light pleasing to the eye? If yes, why? Once your eyes have been opened, you will discover a whole new dimension in your photographic compositions. With time and experience you will focus and react to the light you perceive.
Spend a significant amount of time experiencing light. This is what separates the great photographers from the good photographers. Be reflective and really learn to see the subtle characteristics of light sources. Observe, sense, and feel the presence of light and appreciate its nuances and variety. Give yourself a photo project, and make "light" your main source of inspiration. It is our role as photographers to capture those special moments, using the best possible light.
You can learn a lot about photography by visiting the same location several times, in a variety of different lighting conditions. Try shooting the same scene (or subject) at different times of day, during different weather conditions, and even during the different seasons throughout the year. Make a point to try this exercise. You will see the dramatic impact these different lighting conditions have on the photos you take.