Your Guide to Understanding Screen Gain

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How Does Screen Gain Affect My Viewing Experience?

Screen gain is a technical term that describes how the material of a projection screen affects the apparent brightness of images projected onto it. A projection screen can be made of materials that make images appear brighter or less bright than the images that come from the projector. Neither is bad in and of itself. It's simply important to choose the right kind of screen for the specific viewing environment.

For the viewer, screen gain can cause a projected image to appear too bright or too dim. It can allow for hot spots that wash out the image in certain parts of the screen, or a limited viewing angle that gives a quality view from only certain seats in the room.

Below, we will review the technical definition of screen gain in detail, examine how it affects the viewing experience in different settings, and consider the gain levels of different screen materials. Then, we will discuss the process of choosing and purchasing a screen to best meet the buyer's viewing needs and locations to do so, such as eBay..

What is Screen Gain?

Screen gain is the apparent increase or decrease in image brightness caused by the material used for a projection screen. It is measured as the ratio between the change in brightness on a particular screen and the standard, neutral reference screen.

The reference screen is defined as a screen that shows images at the same brightness as a board coated with magnesium carbonate, the bright white chalk used by gymnasts and rock climbers to dry their hands. This screen has, by definition, a gain of 1.0 and is the reference against which all other screens are compared.

Low Gain

A screen which shows images less brightly than the reference screen is said to have low gain. Its gain will be identified with a number less than 1.0, such as 0.6 or 0.8. A screen with a gain of 0.6 will be 60 percent as bright as the reference screen.

High Gain

A screen which shows images more brightly than the reference screen is said to have high gain. Its gain will be identified with a number greater than 1.0, such as 1.4 or 2.0. A screen with a gain of 2.0 will be twice as bright as the reference screen.

Is Brighter Always Better?

Many people immediately assume that a brighter, high gain image will represent better picture quality. This is not necessarily true for several reasons.

How Does Screen Gain Affect Picture Quality?

High gain screens reflect brighter images but the image quality drops significantly as you move away from a center-screen view. That is to say, they have a limited viewing angle. They can also be prone to hot spots which are areas that appear brighter than the rest of the screen.

Low gain screens reflect images with less brightness, which can be desirable in a room with less ambient lighting. For technical reasons, the lower reflectivity also allows for a wider viewing angle.

These key differences are summed up in the table below.

Issue to Consider

High Gain Screen

Low Gain Screen

Hot Spots

More likely near center of screen.

Not likely.

Color Shifting

Shifts in red, green, and blue may distort images since high gain screens do not reflect all colors equally.

Color shifting not likely.

Viewing Angle

Narrower angle of quality image. Viewers need to be more directly in front of screen. Fewer seats will see the image as projected.

Wider angle of quality image. Viewers may be seated in a wider arc around the screen. More seats will see the image as projected.

Ambient Light

Compensates for higher ambient lighting in settings such as classrooms, trade shows, and conference centers.

Works well in lower ambient light settings, such as home theaters.

In addition to screen gain, two additional ratings are to be considered in assessing projection screens:

  • Peak Gain: Describes a screen's gain rating at center front, the brightest position.
  • Half Gain Viewing Angle: The angle where brightness drops 50 percent.

Typically, a low gain screen has a higher half gain viewing angle, which means that a wider group of people will see the same view. High gain screens have lower half gain viewing angles.

All considered, a lower gain screen can be an excellent choice in a home viewing environment. Screens with gain above 1.3 are not typically recommended for home theaters, but become useful for trade shows, classrooms, and conference centers.

Home sports viewers will of course want to choose screens at the higher end of the home viewing limit. No one wants to watch the Super Bowl in the dark.

How Do Different Screen Materials Affect Screen Gain?

Different materials affect screen gain and offer different benefits in relation to various front- or rear- projection systems that may be chosen.

Front Projection Screens

Several materials are common for front projection screens.. These fall into three broad categories:

  • Retro-reflective, similar to the reflective material used in traffic signs.
  • Angular reflective, causes light to bounce off at an angle like a ping-pong ball.
  • Illuminative, which reflect a diffuse light.

The impact of these various materials on screen gain and other screen properties is noted below.

Description

Category

Detail

Screen Gain

Standard White Matte Screen

Illuminative

When choosing lower-cost motorized screens,, this is your primary option.

1.0

Light Gray Matte Screen

Illuminative

Some people think this enhances contrast and improves black levels. Others find duller whites problematic. Good with LCD - powered home projectors and often preferable with LCOS projectors..

0.7-1.1

High Contrast White Screen

Angular

Good with DLP home projectors..

1.1-1.5

High Gain without High Contrast

Angular

Good for rooms with higher ambient light. Base colors include white, gray, and have included pink.

1.3-2.0

Glass-Bead Screen

Retro-
Reflective

A form of retro-reflective emulsion, these screens have a rougher surface.

2.5

Retro-Reflective Emulsions

Retro-
Reflective

At the lower end, good for rooms with higher ambient light. At the higher end, extremely bright. Image artifacts become noticeable.

2.8-9.0

The range of screen materials available for front projection is extensive. When deciding which is appropriate, issues to consider in addition to screen gain would include whether the screen is a permanent or motorized installation, if it is to be installed flat or with a curve, and several other factors that can affect both the functional screen gain and the viewing angle.

Rear Projection Screens

Rear projection screens may be simple screens designed to allow the projector's light to pass through or diffuse. Others are considerably more complex technologically, employing elaborate arrays of miniscule lenses, often in combination with technologies designed to increase contrast or light diffusion. Sometimes more than one kind of lens (Fresnel and lenticular) is employed in a single screen.

Description

Detail

Screen Gain

Rigid Plastic Diffusion

Varying tints and optical characteristics are added to meet the requirements of the space where the screen will be installed.

1.0-2.3

Flexible Plastic Diffusion

These flexible screens are offered in varying tints and optical characteristics to meet the requirements of the space where the screen will be installed.

1.0-1.8

Fresnel Lens with Diffusion

Low gain, wide angle.

Varies based on diffusion coating

Fresnel Lens with Lenticular

Fresnel lens screens with lenticular elements are high gain.

3.0-3.5

Fresnel Lens with Lenticular and High Contrast Layer

Fresnel lens screens with lenticular elements and a high contrast layer are considered medium gain, high contrast.

4.0

A wide range of screen types are available for those who use rear projection systems, offering a range of gain levels appropriate to different room configurations.

Is Screen Gain Different for Rear Projection?

The definition of screen gain is essentially the same whether front or rear projection is being considered. The technologies for producing the screens are different, but screen gain still refers to the difference between the reference board and the light at the center front of the screen.

Keep Projector in Mind When Choosing a Screen

Screen gain is only one factor in the perceived brightness of a viewed image. Projector brightness will also affect image brightness. So for a low-light home setting, a very bright projector might require a particularly low-gain screen in compensation. A projector with a lower light might require a higher-gain screen. Alternatively, if the projector to be used in a classroom setting did not have a bright light, then a teacher might want an especially high-gain screen.

How to Shop for Projection Screens

Locating the right projection screen is primarily a matter of deciding what you are looking for. Depending on the lighting and configuration of your room, you may want a screen with a particularly wide viewing angle, that is to say low gain. Manufacturers typically rate screens not only for screen gain, but also the viewing angle and the half gain viewing angle, which is the angle at which brightness is diminished by half. This is useful in determining in a more practical sense how wide a viewing angle a particular screen actually offers.

Depending on your own level of confidence in planning a home theater project, you may wish to consult with a professional to make sure you have covered all the bases. Front- and rear-projection screens may be purchased from specialty businesses that plan and install home theaters, from large electronics stores, from discount stores, and from various online outlets, including eBay..

How to Shop for Projection Screens on eBay

Locating the right projection screen on eBay is mostly a matter of deciding what you are looking for. There are always a great many excellent screens available, so you may want to do some browsing just to sort through your priorities.

When you're shopping for projection screens on eBay, you can start by selecting projection screens,, which are found within the TV, Video & Home Audio and Business & Industrial sections, to get a sense of the options. The selection is very extensive, so if you have already identified manufacturers you prefer, you may limit your selections by manufacturers..

Compare Prices

You will want to figure the cost of shipping into the final cost of your screen, and eBay provides a price sorting option that allows you to do that. Sorting by price also helps you to compare prices between sellers. Significantly different prices sometimes represent bargains but sometimes represent products that are not what they seem to be.

Check Out the Sellers

You may prefer to make your initial selection only from vendors who take returns.. Still, return policies vary and each vendor spells out their return policy details on their product pages.

It is also important to feel comfortable that you are dealing with a reliable vendor.. On eBay, two ways to confirm that a vendor is reliable is to check the feedback left by prior customers and to choose to purchase from top rated sellers.. These are vendors who have demonstrated, over many transactions, that they provide the top levels of reliability and customer service.

Conclusion

The correct overall image brightness for a particular home or business viewing setting will be decided in general by the brightness of the viewing environment and the need for images to be visible across a wide or narrow viewing angle.

Screen gain, along with projector brightness, will together determine how bright the projected image appears. Figures that help the buyer know how wide a viewing angle receives a consistent image and at which angle the image loses half its brightness (half gain viewing angle) assist in knowing how broad an area can successfully enjoy the viewing experience.

To purchase a home or business projection screen that will reflect well on you, it is essential to take screen gain into consideration. This will allow you to choose the screen that gives you and your guests the most comfortable and appealing viewing experience.

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