The intensity of architectural and civic lighting is measured in watts from the 25 watt light output of a sewing machine lamp to the 4,000 watt output of stadium lights. Simply put the higher the wattage the brighter the light.
Some forms of artificial light, like fluorescent lighting, produce an unstable form of light. Fluorescent lighting can produce a wide range of color casts that can best be determined by experimentation. Many digital cameras have a fluorescent light setting for adjusting the white balance.
This photo shot under fluorescent light shows some of the color tinting one would expect
Color temperature, measured in degrees of Kelvin, also varies with the light source. Household tungsten lighting is about 3,200 degrees K and introduces a warming yellow-red cast to an image. Electronic flash units are closer to noon daylight at 6,000 degrees K.and is considered a cool light source, almost blue in nature.
Mixed light sources can create a real problem, for example if your main source is tungsten household lamps but you need to fill in some features with a flash unit the color temperature from the tungsten will be 3,200 K (very warm looking) while that area lit by the flash will be 6,000 K (very cool). One solution is to add a filter to the flash reducing its color temp to 3,200 K and using a tungsten color balance in camera effectivly balancing the two light sources. Another solution would be to reflect the tungsten light into the camera aspect of the subject.
Color correcting and creative color gels are available for modifying the color of any light source.
Several companies make small to large collapsible but highly reflective devices to bounce light. But often just a large white poster board will also work.
Artificial light can often be highly directional resulting in obvious shadows. So adding a fill light, near the camera axis, or using a reflector can soften the shadow affect.
This photo was made with a single desk lamp aimed from above at the subject.
Artificial light can also be modified in several ways. Placing a sheer gauze fabric, or section o metallic window screening, in front on the light will soften its look. A piece of poster board can be placed to block the light from reaching an area you want darkened. Two pieces of poster board held just inches apart can create a slash of light for dramatic effect.
While it’s possible to spend hundreds of dollars on a professional lighting kit, there are alternatives. I discovered several 250-500 watt work lights at neighborhood garage sales and built a small kit for less than twenty dollars, and they came with stands.
In part 2 we will discuss electronic flash units.
Have fun experiment with light and shoot some great photos. Larry Grayam