Video Basics 8: Chapter 8, 9

super (superimposition)

A double exposure of two images, with the top one letting the bottom one show through.

floodlight

A lighting instrument that produces diffused light.

spotlight

A lighting instrument that produces directional, relatively undiffused light with a relatively well-defined beam edge.

fill light

Additional light on the opposite side of the camera from the key light to illuminate shadow areas and thereby reduce falloff; usually done with floodlights.

Gain (Audio Gain)

If there is insufficient light even at the maximum aperture (lowest ƒ-stop number), you need to activate the gain circuits of the camera. Most consumer camcorders do this automatically. On camcorders, studio cameras, and ENG/EFP (electronic news gathering/electronic field production) cameras, the gain is activated either via the camera control unit (CCU) or by a switch on the camera. The gain will boost the weak video signal electronically. High-definition cameras can tolerate a relatively high gain before they show picture "noise," that is, artifacts that show up as colored specks. When video quality is of primary concern, it is better to raise the baselight level than to activate the gain switch.

Windows Used as Back Light

In this interview setup, the lighting is done with a single instrument. A diffused Lowel Omni-light with a light-blue gel acts as the key. The back light is provided by the window, which is kept out of camera range.

Block Organization of Titles

Information is easier to read when the titles are organized in graphic blocks.

Fast Falloff

The change of light to shadow areas on these buildings is very sudden. The falloff is extremely fast, indicating an edge or a corner.

Ellipsoidal Spotlight

The ellipsoidal spotlight produces an extremely sharp, bright beam. It is used to illuminate precise areas. Some ellipsoidals have a slot next to the beam-shaping shutters that can hold a variety of metal sheets with patterned holes. Such metal sheets have acquired a variety of names, depending on the company that produces them or the LD who uses them.

Fluorescent Bank

The fluorescent bank consists of a series of fluorescent tubes. It produces very soft light with slow falloff. You can get fluorescent banks that burn at approximately 5,000K for outdoor light or at 3,000K for indoor light. The manufacturers of fluorescent lights try hard to make the light look similar to that of incandescent floodlights, without the telltale greenish look of the fluorescents.

Last-Minute Lighting Techniques

When you are called upon to do some eleventh-hour lighting, do not whine about artistic integrity or lack of time. Simply turn on as many floodlights as possible and try to place some back lights to give the scene some sparkle. This is not the time to fret about triangle principles or falloff. Every so often such an emergency technique will result in surprisingly good lighting—but don't rely on it.

Attached Shadows Emphasized

With the light coming from the side, the attached shadows on this Aztec Sun Stone are more prominent, and the rich, deep texture is properly emphasized.

RGB

basic colors of TV

back light

illumination from behind the subject and opposite the camera; usually a spotlight

digital video effects (DVE)

visual effects generated by a computer or digital effects equipment in the switcher or by a computer with effects software

character generator (CG)

A computer dedicated to the creation of letters and numbers in various fonts. Its output can be directly integrated into video images.

Two-Camera Interview Lighting

A fast and effective way of lighting two people sitting opposite each other is to place a floodlight behind each person in an over-the-shoulder position.

wipe

A transition in which one image seems to "wipe off" (gradually replace) another from the screen.

light plot

A plan, similar to a floor plan, that shows the type, size (wattage), and location of the lighting instruments relative to the scene to be illuminated and the general direction of the light beams.

Title Outside of Essential Areas

A) Although we can read the complete title on a well-adjusted monitor... B) ...the information that lies outside the essential area gets lost on the home receiver.

Beam Control of Fresnel Spotlight

A) To flood (spread) the beam, turn the focus knob, ring, or spindle so that the lamp-reflector unit moves toward the lens. B) To spot (focus) the beam, turn the focus knob, ring, or spindle so that the lamp-reflector unit moves away from the lens.

Shadows

Although we are quite conscious of light and light changes, we are usually unaware of shadows, unless we seek comfort in them on a particularly hot day or if they interfere with what we want to see. Because shadow control is such an important aspect of lighting, let's take a closer look at shadows and how they influence our perception.

Portable Spotlights

Although you can, of course, take small Fresnel spotlights on-location, there are portable spotlights that are hybrids of spots and floods. To keep their weight to a minimum, these portable spots are relatively small and open-faced, which means they do not have a lens. Without a lens, they cannot deliver as precise a beam as Fresnel spots, even when in the focus position. All are designed to be mounted on a light stand or with a clip-on device. One of the more popular models is the Lowel Omni-light.

Light Intensity

An important aspect of lighting is controlling light intensity, or how much light falls onto an object. Also called light level, light intensity is measured in American foot-candles or in European lux. A foot-candle is simply a convenient measurement of illumination—the amount of light that falls on an object.

Attached Shadows Define Shape

Attached shadows help define the basic shape of the object. Without attached shadows, we perceive a triangle on the left; with attached shadows, we perceive a cone on the right. Attached shadows also contribute to perception of texture. A great amount of prominent attached shadows emphasizes texture; without them things look smoother. Attached shadows on a Styrofoam ball make it look like a moonscape; but when the attached shadows are removed through flat lighting, the ball looks smooth.

Energy-Efficient Spotlight

The incandescent quartz Fresnels are being challenged by the more efficient HMI spots that can produce an amazing amount of light with lamps in the 100W to 500W range.

Measuring Contrast

To measure contrast, point a reflected-light meter close to the bright side of the object, then close to the shadow side. (You will read more about measuring contrast in the next section.) The light meter reads the reflected light, first of the bright side (a high reading) and then of the shadow side (a low reading). If, for example, the light meter reads 800 fc in an especially bright area, such as one side of the reporter's face in direct sunlight, and only 10 fc in the dark background, the contrast ratio is 80:1 (800/10=80). Even with a fairly good digital camcorder, this contrast may be too high for good pictures.

lux

European standard unit for measuring light intensity

baselight

Even, nondirectional (diffused) light necessary for the camera to operate optimally. Refers to the overall light intensity.

chroma key

Key effect that uses a color (usually blue or green) for the key source backdrop. All blue or green areas are replaced by the base picture during the key.

attached shadow

Shadow that is on the object itself. It cannot be seen independent of (detached from) the object. The shadow opposite the light source (window or lamp) on the cup is the attached shadow. Even if you wiggle the cup or move it up and down, the attached shadow remains part of the cup.

cast shadow

Shadow that is produced by an object and thrown (cast) onto another surface. It can be seen independent of the object. The shadows of telephone poles, traffic signs, or trees cast onto the street or a nearby wall are all examples of cast shadows. Even if the cast shadows touch the base of the objects causing them, they remain cast shadows and will not become attached ones. Cast shadows are usually cast by an object onto some other surface. In this case the cast shadows of the railing fall on the boards of the bridge.

key

an electronic effect in which the keyed image (figure - usually letters) blocks out portions of the base picture (background)

Outdoors - Overcast and Shadow Area

A foggy or overcast day is ideal for outdoor shooting. The fog and the clouds act as giant diffusion filters: the giant and brutally bright spotlight of the sun becomes a huge but gentle softlight. The highly diffused light produces slow falloff and transparent shadows. The camera likes such low-contrast lighting and produces crisp and true colors throughout the scene. The scene is basically illuminated by high-intensity baselight. Be sure to white-balance the camera before video-recording; the light on an overcast day has a surprisingly high color temperature (bluish tint).

High-Definition Television Aspect Ratio

The HDTV aspect ratio is 16 units wide by 9 units high, or 1.78:1.

Principles of Graphics

The basic elements and principles of video graphics include aspect ratio, essential area, readability, color, animated graphics, and style.

Basic Photographic Principle

The basic photographic principle uses a key light, a fill light, and a back light. They are arranged in a triangle, with the back light at its apex, opposite the camera.

Smooth Texture

Here the attached shadows are almost eliminated, so the surface of the ball looks relatively smooth.

Indoors Without Windows

If the room is adequately illuminated, try to shoot with available light and see how it looks on the monitor. We discussed earlier that the high light-sensitivity of camcorders and ENG/EFP cameras enables DPs to shoot much more often in available light than was previously possible. The basic rule still applies for available light: if it looks good to you, there is no need for additional instruments.

Additive Color Mixing

If you had three identical spotlights, you could put a red color media, usually called gel, into one, a green gel in the second, and a blue gel in the third and aim them at a wall so that their beams overlapped slightly. What you would perceive is similar to the three overlapping circles shown in the figure. When mixing colored light, the additive primaries are red, green, and blue. All other colors can be achieved by mixing certain quantities of red, green, and blue light. For example, the additive mixture of red and green light produces yellow.

background light

Illumination of the set pieces and the backdrop. Also called set light.

Measuring Illumination

In critical lighting setups, before turning on the cameras you may want to check whether there is enough baselight and whether the contrast between the light and dark areas falls within the acceptable limits (normally 50:1 to 100:1, depending on the camera; see Contrast on the following page).

high-key lighting

Light background and ample light on the scene. Has nothing to do with the vertical positioning of the key light. High-key lighting shows a bright scene with an abundance of diffused light. The background is usually light. The background is usually light and projects a high-energy, upbeat feeling. Game shows and situation comedies are usually lighted high-key. Because of the slow falloff, high-key lighting is also used for commercials that advertise beauty products.

directional light

Light that illuminates a relatively small area and creates harsh, clearly defined shadows. The sun, a flashlight, and the headlights of a car all produce directional light. You can aim directional light at a specific area without much spill into other areas.

Studio Lighting Better with Spotlights and Floodlights

Lighting battens consist of a large grid of steel pipes that supports the lighting instruments. In this case, the batten can be lowered or raised using a counterweight system.

Operation of Lights

Lighting presents some obvious hazards. Ordinary household current is powerful enough to kill. As just pointed out, the lamps, barn doors, and sometimes the instruments themselves get so hot that they can cause serious burns. If placed too close to combustible material, lighting instruments can cause fires. The instruments with barn doors are suspended far above studio floor areas and, if not properly secured, can come crashing down. Staring into a bright, high-intensity light beam can cause temporary vision problems. Even so, you don't need to be intimidated and give up lighting before getting started. You can easily eliminate these hazards by observing a few safety rules.

Indoors with Window

By now you know that windows can present a formidable lighting problem. Even if you don't shoot against them, they admit a great amount of high-color-temperature light. If you try to augment the bluish 5,600K outdoor light with normal 3,200K indoor lighting instruments, the camera will have trouble finding the correct white balance. The simplest way to match the lower 3,200K indoor color temperature with the prevailing 5,600K outdoor color temperature is to attach a light-blue gel (color media) to the indoor lighting instruments. The blue gel helps raise their color temperature to approximate the 5,600K outdoor light. Even if it is not a perfect match, the camera can be properly white-balanced for both the light coming through the window and the indoor lighting instruments.

contrast

Difference between the darkest and lightest areas of the image. Contrary to your eye, which can distinguish subtle brightness steps over a contrast ratio with a wide range, even high-end video cameras may be limited to a lower contrast range. Whereas some equipment salespeople might tell you that high-end video cameras can tolerate a contrast that is close to that of our vision, LDs and VOs say that too high a contrast is one of the most common obstacles to producing optimal video.

low-key lighting

Fast-falloff lighting with dark background and selectively illuminated areas. Has nothing to do with the vertical positioning of the key light. The background and, wherever necessary, the floor areas are kept dark. Most outdoor night scenes exhibit low-key lighting. It is also frequently used in dramatic scenes in daytime serials, mystery and crime shows, and sometimes sci-fi movies. Low-key lighting shows dramatic, selective lighting with fast-falloff attached and prominent cast shadows. The background is usually dark.

Lowel Pro-Light

The Pro-light is a small, powerful (250W) ENG/EFP spotlight that can be handheld, clipped to the camera, or mounted on a light stand. With its lenslike prismatic glass, it produces an exceptionally even beam.

Standard-Definition Television Aspect Ratio

The SDTV aspect ratio is 4 units wide by 3 units high, or 1.33:1.

triangle lighting

The arrangement of key, back, and fill lights. Also called three-point lighting and photographic principle.

Slow Falloff

The attached shadow on this balcony gets gradually darker. The falloff is relatively slow, indicating a curved surface.

Reversal of Attached Shadows

The below-eye-level light source causes the attached shadows to fall opposite their expected positions. We interpret such unusual shadow placement as spooky or mysterious.

Color Television Receiver and Generated Colors

The best way to explain the formation of a color video image is to use an old standard color television set. Instead of the three spotlights we used for additive color mixing, a CRT (cathode ray tube) color television receiver uses three electron guns in the neck of the picture tube that shoot their beams at myriad red, green, and blue dots—pixels—on the inside of the television screen. One of the three guns hits the red dots, the other the green dots, and the third the blue dots. The harder the guns hit the dots, the more they light up. If the red gun and the green gun hit their dots with full intensity with the blue gun turned off, you get yellow. When all three guns fire at full intensity, you get white; at half intensity, you get gray. All three guns work overtime when you are watching a black-and-white show on a CRT color television set. In flat-panel displays, the same principle of additive color mixing applies, but the system of electrically activating the RGB pixel clusters is quite different.

Key Light

The key light is the principal light source. It reveals the basic shape of the object. A spotlight is generally used as a key. As you can see, the key light is not defined by the instrument used but by its function: to reveal the basic shape of the object. The key light is usually placed above and to the right or left of the front of the object. Note that when a spotlight is used as a key, it produces fast falloff (a dense attached shadow); when you use a floodlight, the falloff is slower and the shadows are more transparent.

Background Light

Unless you want a dark background, you need additional light to illuminate the background or set. This additional source is called the background light or set light. For a small set, you may need only a single Fresnel spot or scoop. SEE 8.36 A large set may require a few more instruments, each of which illuminates a specific set area. To keep the attached shadows of the background on the same side as the foreground shadows, the background light must be on the same side of the camera as the key light. The background, or set, light illuminates the background and various set areas. Spots or floodlights are used on the same side as the key.

Portable Floodlight

When choosing a portable floodlight, look for one that is small, produces a great amount of diffused illumination, has a reflector that keeps the diffused light from spilling all over the area, can be plugged into an ordinary 120-volt (V) household outlet, and is lightweight enough to be supported by a light stand. You can, however, use any type of portable lighting instrument as a floodlight if you diffuse its beam.

Bright Sunlight

When forced to shoot in bright sunlight, you are not so lucky. The bright sun acts like a giant high-intensity spotlight, which renders the falloff appropriately fast; the shadows are very dense, and the contrast between light and shadow sides is extremely high. This extreme contrast can present a formidable exposure problem. If you close down the iris (high ƒ-stop setting for a small aperture) to prevent too much light from overloading the sensors, the shadow areas will turn uniformly dark and dense and will show no detail. If you open up the iris to see some detail in the shadow areas, you will overexpose the bright areas. The automatic aperture in a camcorder is of no help in this situation: it simply adjusts to the brightest spot in the scene and renders all shadow areas equally dark. Even the most sophisticated camera cannot adjust itself to accommodate these conditions.

Field Lighting

Whereas studio lighting is done exclusively with various types of instruments, field, or location, lighting often extends to the control or augmentation of available light. When shooting outdoors you are pretty much dependent on available light. Your lighting job is to manipulate sunlight so that it yields, at least to some extent, to the basic lighting principles. When shooting indoors you can apply all studio lighting principles, except on a smaller scale. Windows often present a problem because the light entering from outside is usually brighter than the indoor light and has a much higher color temperature. But light from windows can also be an important illumination source.

Use of a Single Panel

You can use a single softlight panel from the front and a little off to the side of the camera for a stationary subject. To light an ordinary-sized room so that you can follow somebody walking through it, use the portable lights in the flood position and reflect them off the ceiling or walls, or diffuse their beams with scrims. If available, use a light-diffusing umbrella.

Chinese Lantern

These floodlights produce highly diffused light over a large area.

Disorganization of Titles

Visual clutter occurs when the information is not graphically organized. The scattered bits of information are hard to perceive, especially on a video screen.

aspect ratio

ratio of the width if the television to its height

Simple Light Plot Sketch for Two-Person Interview

Most light plots are rough sketches that indicate the types of lights used (spots or floods), their approximate positions, and the general direction of their beams.

Standard Two-Camera Interview

Most often you will be called upon to light an interview in some room with the interviewer and interviewee sitting in chairs opposite each other. You can light such a setup quite effectively with two softlights or with small Omni-lights in flood positions with diffusers. Place the cameras first for the desired cross-shots, usually tight close-ups. Note that both cameras must be either on the left side or the right side of the vector line—the virtual line created by the converging index vectors of the two people. Then place the lights next to or behind the cameras so that they are out of the shots.

Scoop (type of floodlight)

Named after its scooplike reflector, the scoop is an old-fashioned but highly useful floodlight. Scoops can be used as key lights as well as fill lights for dense shadow areas to slow down falloff and make shadows more transparent. They are ideal for lighting large areas with relatively even light. To diffuse the light beam even more, you can attach a spun-glass scrim to the front of the scoop.

Types of Light

No matter how the light is technically generated, you will work with two basic types: directional and diffused.

key light

Principal source of illumination; usually a spotlight.

Rough Texture

Prominent attached shadows emphasize texture. The surface of this Styrofoam ball looks rough.

additive primary colors

Red, green, and blue. Ordinary white light (sunlight) can be separated into the three primary light colors. When these three colored lights are combined in various proportions, all other colors can be reproduced.

color temperature

Relative reddishness or bluishness of white light, as measured on the Kelvin (K) scale. The norm for indoor video lighting is 3,200K; for outdoors, 5,600K. Keep in mind that color temperature has nothing to do with how hot the actual light source gets. You can touch a fluorescent tube even though it burns at a high color temperature; but you wouldn't do the same with the incandescent lamp in a reading light, which burns at a much lower color temperature. Because color temperature is measured by the relative bluishness or reddishness of white light, couldn't you raise the color temperature of an indoor light by putting a slightly blue filter in front of it, or lower the color temperature of an outdoor lamp by using a slightly orange filter? Yes, you can. Such color filters, known as gels or color media, are a convenient way of converting outdoor instruments for indoor lighting and vice versa.

Diffusion Tent

Small portable lights, including spotlights, can be made into effective softlights by diffusing their beams with light tents.

Clip Light with Barn Doors

Small spotlights, which use ordinary internal reflector lamps, are useful for illuminating small areas during field productions.

Cookie Pattern

Some ellipsoidal spotlights double as pattern projectors. You can insert a variety of metal cutouts, called cookies, whose patterns are projected by the spotlight onto a wall or other surface.

Use a Reflector

The reflector acts like a fill light: it bounces some light back toward the dense shadow areas and slows down falloff. Avoid shooting against any bright background, such as a sun-drenched white wall, the ocean, or a lake. Anyone standing in front of it will be rendered in silhouette unless you use huge reflectors or high-intensity fill lights. Whenever possible find some shade in which to position the subject. When shooting at a lakeshore or the ocean beach, use a large umbrella to create the necessary shadow area. The umbrella will not only make your lighting job considerably easier but also provide some visual interest.

Scoop with Scrim

The scoop like reflector of this floodlight allows you to give its diffused beam some direction, which makes it a good fill light. With a scrim attached to its otherwise open face, it acts more like a broad.

essential area

The section of the television picture that is seen by the home viewer, regardless of minor loss during signal transmission or signal processing by the television receiver. Also called safe title area. The essential, or safe title, area is centered within the TV screen. All necessary information must be contained in the essential area.

falloff

The speed (degree) with which a light picture portion turns into shadow areas. Fast falloff means that the light areas turn abruptly into shadow areas and there is a great difference in brightness between light and shadow areas. Slow falloff indicates a very gradual change from light to dark and a minimal brightness difference between light and shadow areas.

photographic principle

The triangular arrangement of key, back, and fill lights. (three-point, lighting)

foot-candle (fc)

The unit of measurement of illumination, or the amount of light that falls on an object. One foot-candle is 1 candlepower of light (1 lumen) that falls on a 1- squarefoot area located 1 foot away from the light source.

Fresnel Spotlight

The workhorse of studio lighting. Its lens creates a relatively sharp light beam that can be partially blocked by barn doors. This spotlight can be focused, tilted up and down, and panned sideways by turning the knobs with a lighting pole (a wooden pole with a metal hook at the end).

Strip or Cyc Light

These instruments are used primarily to illuminate cycloramas, drapes, and large scenic areas. They are similar to theater border lights and consist of rows of four to 12 quartz lamps mounted in long, boxlike reflectors. These strips are usually positioned side by side on the studio floor and shined upward onto the background. SEE 8.29 There are LED strip lights available that can light up a cyc portion with a great many colors without the need for color gels.

HMI Fresnel Sporlight

This HMI Fresnel spot has a built-in ballast. It has a very high light output with relatively low-wattage HMI lamps.

Softlight

This floodlight is covered with diffusing material and delivers extremely diffused light. It causes very slow falloff and renders shadows virtually invisible.

LED Light Panels

This large 12-by-12-inch LED light panel is dimmable, generates very little heat, draws little power for an amazingly high light output, and burns longer than any kind of incandescent lamp. LED stands for light-emitting diode, and the lights operate on an illumination additive RGB color principle that is similar to the way a computer screen works. When a computer screen is turned on, it can generate enough light to illuminate an object right next to it. If you colorize the screen, you can colorize a nearby white object without having to use color media.

Detailed Light Plot Sketch for Two-Person Interview

This light plot shows the type and position of the lighting instruments used and the approximate directions of their beams. Sometimes light plots even indicate the size (wattage) of the instruments. Note that there are two overlapping lighting triangles—one for person A and the other for person B.

Lowel Omni-Light

This popular lightweight instrument doubles as a spot and a floodlight and is used mainly in ENG/EFP. You can plug it into any normal household outlet and hold it or fasten it to a light stand or any other convenient mounting device.

Small EFP Floodlight

This small EFP floodlight (Lowel V-light) runs off ordinary household current and can be used to illuminate small areas. When mounted inside an umbrella reflector, it serves as a softlight.

Bold Letters Over a Busy Background

This title reads well despite the busy background. Its letters are bold and have enough contrast from the background to ensure readability.

Two-Point Indoor Lighting

To achieve effective triangle lighting with only two lights, use one for the key light and the other for the back light. Fill light is achieved with a reflector.

white-balance

To adjust the color circuits in the camera to produce white color in lighting of various color temperatures (relative reddishness or bluishness of white light). When white-balancing, the camera adjusts the RGB signals electronically so that they mix into white. Most small camcorders have an automatic white-balancing mechanism. The camera measures more or less accurately the color temperature of the prevailing light and adjusts the RGB circuits accordingly. To counteract tinting caused by variations in color temperature, you must white-balance the camera. This adjusts the RGB channels to compensate for the unwanted color cast and make white look white.

Attached Shadows Minimized

To emphasize the smoothness of the model's face, attached shadows are kept to a minimum. Another example, with the light shining directly on the Sun Stone, the lack of attached shadows makes the intricate carvings look relatively flat.

Back Light

To outline the subject more clearly against the background, and especially to give the hair—and with it the whole picture—some sparkle and luster, you need a back light. Some lighting people believe that it is the back light in particular that gives the lighting its professional polish. (See 8.34) The back light outlines the subject against the background and provides sparkle. Focused spots are used as back lights.

Fill Light

To slow down falloff and thereby render dense shadows more transparent, you need a fill light. A floodlight is generally used, but you can of course also use a Fresnel (or any other spotlight) for fill. Obviously, you place the fill light on the side opposite the key light and aim it toward the shadow area. SEE 8.35 The fill light slows down falloff and renders shadows more transparent. Floodlights are generally used to fill in dense shadows.

diffused light

light that illuminates a relatively large area and creates soft shadows. A good example of diffused light occurs on a foggy day, when the fog operates like a huge diffusion filter for the sun. Observe the shadows in bright sunlight and on an overcast or foggy day; they are quite distinct and dense in sunlight but hardly visible in fog. The fluorescent lighting in elevators and supermarkets is a good example of diffused indoor light. It is used to minimize the harsh shadows on a face or an object and to illuminate large areas.

reflected light

light that is thrown back or bounced off an object; measured by pointing light meter close to he object from the direction of the camera. Be careful not to block the light whose reflection you are trying to measure. As mentioned before, the difference between the two readings will indicate the lighting contrast. Note that the contrast is determined not only by how much light falls on the object but also by how much light the object reflects back into the camera. The more reflective the object, the higher the reflected-light reading will be. A mirror reflects almost all the light falling onto it; a black velour cloth reflects only a small portion.

incident light

light that strikes the object directly from its source; to measure, point the light meter at the camera or into the lighting instruments. Such a quick reading of incident light is especially helpful when checking the prevailing light levels at a remote location. If you want a more specific reading of the light intensity from certain instruments, point the light meter into the lights. To check the relative evenness of the incident light, point the light meter toward the principal camera positions while walking around the set. If the needle or digital read-out stays at approximately the same intensity level, the lighting is fairly even. If the needle or read-out dips way down, the lighting setup has "holes" (unlighted or underlighted areas).

mate key

the key (usually letters) is filled with a specific color

LED lights (light emitting diode)

the small lamp is a solid-state device that changes electric energy into light energy. It burns with a high-intensity beam yet consumes less power than other lamps