Almost all projector manuals recommend turning off all ambient lighting for the best results.
So, whenever you want to watch a movie on the big screen you close the shutters and turn off all the lights, completely blacking out your room.
Surely there must be another way to enjoy your projector’s image without locking yourself in a dark room.
Lucky for you, light-rejection projector screens allow you to watch content on your projector in a well-lit room.
What are ALR and CLR screens, and how do they work?
How do they differ from each other?
Open the curtains and turn on the lights, because today we’re learning about the wonderful world of light-rejection technology!
Let’s get started!
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Why Is Light Rejection Important in Projector Screens?
Light rejection is important to ensure a bright and high-contrast projector image.
Using a projector in a well-lit room will cause even the brightest units to look dimmer than they would in a dark room.
The ambient light fades out the image, making it appear darker and less vivid. You may find the colors aren’t as bright as usual and that you struggle to see detailed images.
Additionally, projector screens that don’t have light-reflecting technology often have a noticeable glare when used in a brightly-lit room.
This phenomenon is called spotlighting, which describes bright spots on the screen, making it difficult to see the image.
For instance, you may see a reflection of your lamp’s light or the sun’s rays coming through the window.
Light-reflecting screens combat spotlighting using anti-glare technology by using repeated optical structures, meaning the screen’s surface is not smooth, even if it appears to be to the naked eye.
So, you can use your projector in a well-lit room and still be able to clearly see the image.
What Is an ALR Projector Screen?
ALR stands for Ambient Light Rejection.
ALR screens are equipped with ambient light-rejecting technology, which only displays light from sources directly in front of it.
It “rejects” ambient lighting by reflecting it back so that it’s not visible on the screen.
If you were to place your projector on a table or ceiling mount it in front of an ALR screen, you would only see the light coming from your projector.
The projector and your seating must also be centered in front of the screen.
However, if there were a window or bright light source behind your projector, the screen’s ALR technology would be ineffective, since it would also display that light as well.
ALR screens can only reflect light that’s not coming from the same direction as the projector (or from directly in front of it).
This allows users to play content on their projector during the day and still see a bright and clear image that has a great contrast ratio and decent black levels.
It should be said, however, that ALR screens will not make projectors look as bright as they do in complete darkness.
For the best results, use a projector that is bright enough to be seen in ambient lighting. We recommend looking for a projector with at least 1500 lumens.
How Do You Use an ALR Projector Screen?
Whenever using any kind of projector screen, you must ensure it’s laying flat against the wall and not wrinkled.
You must put your projector directly in front of the ALR screen, as opposed to putting it to the side and projecting the image at an angle.
You can place the projector on a tabletop or mount it to the ceiling. ALR projector screens can also be used with ultra-short throw units.
Eliminate any light sources that are behind the projector, such as lights or bright windows.
We also recommend increasing your projector’s brightness for the best viewing experience possible.
What Is a CLR Projector Screen?
CLR stands for Ceiling Light Reflection.
Like ALR screens, CLR screens also reject ambient light to ensure your projector looks as luminous as possible in a bright room.
However, CLR (or ceiling light reflecting) screens specifically combat lighting from above. CLR screens are especially helpful if you have overhead lights or a skylight window in your home.
They’re also great for offices as they usually have bright ceiling lights that can make a projector’s image difficult to see.
Additionally, they help decrease the appearance of ambient lighting from all directions.
Instead of reflecting light, CLR screens “reject” it by absorbing it, which is extremely effective. They can absorb up to 95% of ceiling light, making them the perfect solution for brightly lit spaces.
Since they absorb light, as opposed to reflecting it, CLR screens often make a projector’s image look high-contrast and ultra-bright.
However, you will achieve the best results using a bright, high-resolution projector with a good contrast ratio.
How Do You Use a CLR Projector Screen?
CLR screens can not be used with ceiling-mounted projectors, as they will absorb the projectors’ light since it’s coming from above.
Some CLR screens specifically state that they can only be used with ultra-short throw (UST) units placed on a tabletop.
So, please check your CLR projector screen’s instructions before purchasing it to ensure it’s compatible with your projector type.
Set up your CLR projector screen, ensuring it’s wrinkle-free. Then set up your compatible projector. Remember, it can not be ceiling-mounted.
Your projector must be placed directly in front of your screen. Don’t forget to make your projector brighter for the best results.
Differences Between ALR and CLR Screens
There are a few key differences between ALR and CLR screens.
ALR and CLR screens both help make projectors appear clearer and more luminant in bright rooms.
However, they differ in the way they target light, which projector types they’re compatible with, and how they control ambient lighting.
Let’s learn about them!
The Direction of Light
ALR screens target light from all directions except directly in front of them where the projector is placed.
They’re great to use if you have a tabletop or floor lamps around your room, or big windows that let in a lot of sunlight. So, think of ALR screens as the perfect solution to a generally bright space.
On the other hand, CLR screens specifically target overhead light, however, they also help with ambient lighting too.
So, if your home has a sunroom, windows on the ceiling, or an abundance of overhead lights, then CLR screens are the perfect choice for you!
Type of Projector
One great thing about ALR screens is that they can be used with virtually any type of projector, be it ceiling mounted, ultra-short throw, or tabletop.
This makes them a perfect home theater staple since they’ll always come in handy even if you buy a new projector.
Meanwhile, many CLR projectors can only be used with ultra-short throw projectors, which doesn’t make them a viable option for most people.
The ultra-short throw projector should be on a tabletop directly in front of the screen, giving you a lot less flexibility when designing your home theater.
How Ambient Lighting is Controlled
ALR screens reflect ambient light, meaning the light bounces off the screen so it doesn’t fade the image.
However, ALR does not dim your projector’s light as it selectively reflects ambient lighting from the sides of the screen.
They’re also easier to use since you only have to position the projector front and center.
CLR screens mainly function to diminish the appearance of ceiling light, so the screen is specifically crafted to absorb any light shone from above.
Because CLR screens absorb light, you must correctly set up your projector to ensure it doesn’t absorb the image’s luminance.
If you set up your unit incorrectly, the image could become very dark and dull as up to 95% of it will be absorbed by the screen.
Comparison Table
| ALR | CLR | |
| The Direction of Light | Eliminates ambient lighting from the screen’s sides | Eliminates overhead lighting |
| Type of Projector | All projectors | Mainly UST tabletop projectors |
| How Ambient Lighting is Controlled | Reflects ambient light | Absorbs overhead light |
Wrapping Things Up
At first glance, ALR and CLR screens seem very similar, but they serve fundamentally different purposes.
ALR tackles all ambient light while CLR targets overhead light.
When deciding which one is right for you, consider your home theater’s setup and the type of projector you have.
If you’re looking to ceiling mount your unit, we suggest sticking with an ALR screen.
If you have an ultra-short throw unit in a skylit room, consider getting a CLR screen.
Remember to always check what kind of projectors and setups the manufacturer recommends using a projector screen with before purchasing it to ensure they’re compatible.
What’s your experience using ALR or CLR screens? Let us know in the comments below!
Yesenia Achlim is a technical copywriter and editor with a focus on AV equipment. She aims to break down complicated topics and make technology accessible, no matter your technical expertise. When she’s not teaching you how to replace a projector lamp, you can find her reading and baking.