Basic Lighting

“Let there be light”, basic lighting tips for photo and video
First, a word of caution. Whenever you deal with lighting use common sense, you are dealing with electricity sometimes in highly charged form, they often get very hot and will burn you or anything to close, lighting equipment is expensive, treat it with respect and care.
There are many considerations to take into account when deciding how to light your project. Is this still photography or video-film? Some lighting options are restricted to still photography, while other continuous lighting can be used with both. Much of the jargon and techniques are shared by both disciplines, however there are some differences.
Strobes: This type of light source is restricted to still photographs, essentially it uses a battery style power pack to store a large source of power that can be discharged in a single flash. Video and film require the use of a constant light source. One advantage that strobe has is that the power packs used can deliver a variable amount of light, capable of delivering more power in a single burst than continuous lights and often capable of delivering  much smaller amounts of light as well.
This type of lighting is what is most often used by still photographers, for a variety of subject matters from people to products, however continuous can also be used.
Generally speaking a constant light source delivers a less intensive light which means that the exposure will have to be more carefully considered from the camera standpoint, such as ISO, shutter speed and aperture.
Hot Lights: This is a term often used for continuous lighting. This type of lighting can be thought of as similar to incandescent lighting in your home, you turn on the switch and it delivers a certain amount of light-depending on the wattage of the bulb, continuously until you shut the switch off again. Most of the time the wattage or the intensity of the light is not variable, however there are exceptions. One way to increase the amount of light on your subject is somewhat obvious, move the light closer to your subject, this can also be true for strobes however you may be able to simply increase the power output on the pack and not have to move your light. That being said, moving the light closer changes the nature of the light by making it a bit softer, which sometimes can be to your advantage. Hot lights come in various forms, they may use the same incandescent house bulbs you are used to, but you can get different types of bulbs to use in them, such as photo-floods or florescent bulbs. Some may be LED lights (which sort of makes them not-hot lights) these lights use much power to operate and also run at a much lower temperature making them a safer option. Other lights are especially designed for video and film such as HMI lights, these are the types of lights you probably most associate with movie and TV production, ARRI is one of the manufacturers that is well known for making these types of lights. One of the variables from all of these light sources is color they produce.
Color Temperature: The color temperature of light is measured in a scale of degrees Kelvin. Average household light bulbs are about 3200 K, they give off a very warm yellow-orange light. Strobes are normally balanced for daylight temperature, which is around 5000 K. However there are many options for controlling the temp of your lights. Some lights can be variable in the temp they produce, such as some of the latest LED lights. You can also buy a range of different bulbs that produce a specific color balance, such as photo-floods which are daylight-5000 K, some florescent bulbs are also daylight balanced. Even HMI lights that are normally 3200 k can be purchased to produce daylight. You can also purchase modifiers such as gels to control your color temperature, these are often referred to as CT (color temp) gels, and come in various colors and densities to help you adjust your lights. Of course for this you will also need a color meter, it looks very much like a normal light meter, but it measure light in the Kelvin scale. Gels are used by still and moving image- makers alike. Ok, now you have the color of your lights under control, how about how your camera sees it?
White Balance: Ok, you have your lights set up and they are the appropriate color temp but when you shoot your still or video the color is completely whacky-what the heck! Back in the stone ages when you shot film you might have purchased different types of film that were designed to work a specific type of light, such as tungsten film to shoot with incandescent lights, or you might have used a special color filter on your lens. Filters for your lenses are still available and there is nothing wrong with using them. However if you are using a digital camera or video camera you can create a custom white balance for your lighting scenario. Most cameras have an automatic white balance feature, which often works fine, but not always, you may also have the option to choose from various white balance modes that are built into the camera, such as incandescent or florescent. To create your own white balance navigate to that feature in your camera menu, then place a white card in your scene where the light you are using falls, now fill your frame with the white card only and use this image to create your custom white balance. This should give you a color balanced image, that being said, if you have multiple light sources with various color temps this will be an issue, but even that can be used to a creative end.
Control: Now that you have chosen the right lights for the job and have your color balanced what are the other options you have to control your lighting situation? Metering the intensity of your light will be important, you can use your in camera meter or a hand held one, which has greater control in that can place it in the various areas of your scene to meter different sources of light fall-off. Another important factor is the quality of light being used, as in is it a hard or soft light.
Some of the light sources being used will help determine that, but something else to consider are modifiers. What I mean by that is anything that can be use to change the nature of the light, from things that can soften or harden the light or bend, bounce, reflect light. Some things can be used to shape light, create shadows, colors.
There are allot of options, allot of which can be low-cost creative methods that utilize common materials. As mentioned earlier one simple things is moving the light source, the closer the light is placed to the subject the softer the light becomes and conversely the farther away it is the harder it is, good for casting shadows.
You can use specialty modifiers like light boxes to soften the light, the bigger the box the softer the light, and many of these have various pieces or layers to help refine the softness. You can also take the DIY approach and use different materials such as a sheet or vellum or bouncing the light off a white surface, please use caution, most of these lights can and will ignite materials that are too close to the light source. Reflectors can be used to control the circle of light projected, some are hard-shiny ones that can intensify the light while others are softer or textured to reduce glare. Some reflectors can hold things like grid spots to narrow the circle of light, to some you can attach barn doors that help to control the light, keeping it off one part of your scene while letting it fall on another. Some lights or reflectors can hold umbrellas to bounce the light, while some are designed to shoot through. Other things can be use to reflect light from the source such as white cards-foam core, mirrors, metal, custom reflectors can be purchased, simple white ones, silver or gold ones, some are designed to be portable folding up neatly into their own case. Experiment and get to know different materials and devices, but use common sense and be safe.
What’s Your Angle: The placement of your lights is one of the most important decisions you can make. There are several terms in lighting that are used by both photo and video. Key light, this light determines the general direction and mood to be set in your scene and usually corresponds to you main subject. You can think of this as the sun, it is your main light source. The general rule is that this light does not come from the front, but rather the side to increase dramatic effect, as always this rule can be broken if it works with your concept. Fill light, this is usually a softer light that used to increase the overall brightness of the scene and helps reduce shadows, a modifier is often used and is usually employed as an indirect light source-not pointed directly at the subject. Background light, just like the name implies this is the light that is used to illuminate the background behind the subject, it can be hard or soft, anything that works with the mood of the scene. A Hair-Separation light is used to illustrate the outline of the subject and help distinguish it from the background, you can often see obvious use of this in movies and television.
Axis light is one not always used or mentioned, this light would come directly from the direction of the camera, usually used to increase the brightness of the scene and to help reduce shadows, a common example is a ring light that goes around the lens.
In the case of copying artwork usually softer light is used and comes indirectly from the side or slightly around in front of the piece being photographed, usually with two lights that are equidistant from the subject. This is only a beginning, lighting is a vast topic with allot of variables, experience is the key to expanding your technique.