Projectors can create an image on any flat surface. So do you really need a screen?
Geoffrey Morrison
Do you need a screen for a projector? Short answer: Technically, no. Longer answer: It depends, but probably yes. Even longer answer: A screen will dramatically improve the image quality, and often the brightness, of any projector. Even a cheap screen can improve the performance of the best projectors. More expensive screens can reduce ambient light, greatly improving image quality if there’s any light in the room. Also, while your painted wall may seem smooth, there’s still a texture, and every tiny imperfection will be visible as part of your movie, TV show or game.
Look at it this way, movie theaters have screens for a reason. Spending even a little money on a screen will improve how the projector you spent a lot of money on looks in any room. It is an added cost, though, plus the added complexity of setup and mounting. So if you’re not sure, here are all the reasons why you should get a screen, especially if you have an ultra-short-throw projector, plus a few situations where you don’t need one.
To screen or not to screen
There are three main reasons to get a screen:
- Brighter image: Even simple screens are better than walls of any color.
- Smoother image: Walls have texture that will be visible in the projected image.
- Potentially better contrast and overall image quality: Some screens can “focus” more light toward your eyes, making the image seem brighter. Others can reject ambient light, so the image is better with any lights on.
Now, in fairness, if you have a tiny, budget projector that puts out only a handful of lumens, you won’t gain much by adding a screen. There’s very little performance to begin with, so there’s not much to improve. Full-size budget projectors and anything more expensive can definitely benefit. Many screens can “add” brightness by focusing more of the light back to where you’re sitting, instead of scattering it all over the room.
That scattering is especially problematic if you have an ultra-short-throw projector. Enough so that I’ve got a whole section below about them specifically.
Regardless of the type of projector, any ambient light in the room will bounce off your wall (or screen) and negatively impact the image. It will wash it out, making it harder to see. There are ambient light-rejecting and ceiling light-rejecting screens that can help considerably if you want to use a projector but also don’t want to live in a cave. More on these below, but keep in mind no screen can magically make your projector look like a TV in the daytime.
Ultra-short-throw projectors need screens
Ultra-short-throw projectors have gotten quite popular, or at least their marketing has. These projectors sit just a few inches from the wall/screen, compared to short-throw projectors (a few feet away) and traditional projectors (many feet away). That placement ends up being a significant issue due to how light bounces off flat surfaces. Without diving too far into the physics of it, what happens is that a large amount of light ends up bouncing off the projection surface into your ceiling. This lightshow is distracting, at best, and depending on your ceiling, can reflect enough light back onto the screen to reduce image quality.
The solution is a special type of screen that helps direct light in specific ways to minimize this unwanted scattering. To test UST projectors, I bought a ceiling light-rejecting screen from Elite. The difference is huge. As you can see:
A number of companies make CLR screens, both in fixed, motorized and manually retracting versions. Due to their more complex optical properties, CLR screens are harder to manufacture than traditional models, making them more expensive. This is something often unmentioned or waved away in the marketing for UST projectors. This is especially concerning since UST projectors are more expensive than similarly performing non-UST projectors. As a package, they’re just really expensive, so if you can fit a traditional projector, or even a regular short throw, they’ll be far cheaper, even with a screen.
ALR vs. CLR
CLR screens are a subset of ALR, or ambient light-rejecting screens. Both can minimize the impact of ambient light. As their names suggest, CLR screens work best when the light is coming from above, which is the main issue with UST projectors, but also if you have recessed lighting above the screen. ALR screens are designed for mixed lighting, aka a standard assortment of lamps, windows, etc.
The manufacturers of UST projectors specifically recommend CLR screens, so it’s best to go with that type if you’re getting one of those projectors. For other projectors, an ALR screen is better for most rooms. That said, the best option for non-UST projectors is room light control. Curtains and turning off the lights will work far better than any screen. No screen is magic, but they can help if you have the budget.
Other important factors to consider (digging deeper)
So that’s all the basics, but if we dig deeper, there’s a surprising amount of physics involved in getting an image from a tiny chip inside a projector, through the air and into your eyeballs. The same projector in two different rooms could have radically different performance. Two of the biggest reasons for this are the placement of the projector and the screen.
As mentioned above, a decent screen is crucial to any projector’s performance. This is because all projectors need to reflect off a surface to be seen at all. That surface does a combination of reflection and absorption, both of which are key in how the image appears to you.
To understand how screens work, it helps to imagine three different surfaces: a thick black curtain, a mirror and a piece of white paper. Shining onto these surfaces is the light from a projector or, if it’s easier to envision, the light from a flashlight.
Firstly, a curtain will absorb most of the light coming from the projector, and the image will appear dim. The same is true, to a lesser extent, if you’re using a wall instead of a screen. Even brighter shades of paint will absorb more light than a dedicated screen.
A mirror, on the other hand, reflects nearly all the light and in such a way that it’s impossible to see the image. The light bouncing off it travels at a specific angle in relation to how it hits the mirror. This analogy is important for screens because most projectors have an upwards throw, so they’re either mounted above the top of a screen or placed on a stand/table below the screen. If the projection surface was a mirror, most of the light would bounce toward the floor (in the case of a ceiling mount) or the ceiling (in the case of a stand/table). This is the issue I mentioned above regarding ultra-short-throw projectors, since the severe angle they are in relation to the screen means that without a special screen, a lot of light gets wasted on the ceiling.
Now imagine a piece of white paper that could, theoretically, reflect light evenly. This surface could combine the best properties of the previous two types by enabling you to: 1) see the image, and 2) get most of the light reflected back to you. However, in reality the paper would scatter the light too much, or at least more than what many screens do, so the image wouldn’t be as bright as it could be.
These extremes should give you an idea of what’s necessary with a screen. At its simplest, a screen has to reflect the light evenly so you can see the image. Beyond that, many screens have additional special coatings that can direct or focus the light. Screens with a positive “gain” can make the image appear brighter where you’re sitting, similar to how a lighthouse beacon’s lens focuses the light so boats can see it farther away.
As mentioned above, CLR and ALR screens take this one step further, not only directing light coming from a sharp angle more toward your eyes, but absorbing or redirecting light coming from different angles so the image isn’t as washed out.
A few companies make reflective paint that you can apply directly to your wall instead of using a screen. Even the smoothest of these can have visible texture, which will show up in the image. They also won’t be able to focus the light as much as a higher-gain screen.
Improving brightness
If a screen isn’t in your budget but you want to improve how your projector looks, there are a few things you can do to improve the image’s brightness. They’re not going to transform a dim projector into a bright one, but they’ll help.
- Size: The first, and perhaps most obvious, is to just make the image smaller. If you don’t have a screen, either at all or yet, experiment with zoom or placement to make the image smaller. A small decrease in size can greatly increase how bright the image is.
- Lamp and laser/LED settings: Most projectors have a setting to increase lamp power to increase brightness. This, unfortunately, has some side effects. A brighter lamp won’t last as long (not an issue with LED and laser-based projectors), so you’ll be replacing it more often. This usually means the projector’s fans will run more and at higher speeds, increasing noise in your room. Some projectors have a Dynamic lamp mode (or another feature with a similar name), which increases the lamp power for bright scenes and decreases it for dark scenes. Typically these extremes are the same as the projector in its brightest and darkest modes.
- Picture settings: We recommend settings to make your projector look its best, but usually that comes at a cost of overall light output. A less accurate mode, either a cooler “bluer” color temperature, or less accurate color mode, will either make the image actually brighter, or at least appear brighter. The cost here is a worse looking image, however.
- New lamp?: If you bought the projector used, or you’ve had it for a while, it’s possible replacing the lamp (if applicable) will make the image much brighter. Many projectors will have a lamp hour counter in the menu that tells you roughly how old the lamp is. You can check online to see how close this is to the recommended replacement life. If you bought it used, it’s possible the seller reset this counter, so be skeptical if it’s a few years old with no hours on the lamp. If you’ve replaced a still-working lamp, save it in case something happens with the new lamp. That way you’ll still have something while you wait for a new replacement. Avoid third-party or knock-off replacement lamps though, as they might be dim compared to their “real” counterparts. However, modern LED and laser projectors don’t have lamps, and so aren’t susceptible to this issue.
Beyond that, it’s just about getting a brighter projector. Fortunately, we’ve got a few picks along those lines.
As well as covering audio and display tech, Geoff does photo tours of cool museums and locations around the world, including nuclear submarines, aircraft carriers, medieval castles, epic 10,000-mile road trips and more.
Also check out Budget Travel for Dummies, his travel book, and his bestselling sci-fi novel about city-size submarines. You can follow him on Instagram and YouTube.
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