Now, projectors are sold even in small electronics chain stores and cost less than jeans. A mass of Chinese LED models with many functions has appeared, which, as it turned out, have a wide variety of uses: organizing spontaneous viewing at home, bringing a projector for entertainment to the dacha or to friends, and if the model is battery-powered, the projector can even be taken on a picnic. Projectors have come to be perceived as an element of everyday life.
But here's the problem — the result, that is, the image quality, does not always match what is imagined when buying. And the reason often lies not in the scarcity of technical characteristics, but in the wrong choice of surface on which the image is projected.
A wall is not an option
According to surveys, many people still believe that any white wall or even a sheet is perfectly suitable for a projector. And not without reason: there was a time when special paints for projection walls were actively advertised, and projector manufacturers even added an image correction function for wall color. But if color correction can still be considered a saving grace for a desperate situation, then the paint option is just a marketing ploy. It is unrealistic to level a wall and paint it so perfectly that no flaws are visible. The projector will highlight even the slightest imperfections. But most importantly, no paint can compete in reflective properties with a specially designed screen.
It's not that projectors are designed to work with special screens — it's just basic physics. A projector and a screen are a single display system, spatially divided into two parts, where the final image quality depends on both components. For example, televisions use specially designed plastic for panels, and not, say, plastic designed for greenhouses, although it also seems transparent and flexible. Only in televisions is it impossible to choose the outer side of the panel for different viewing conditions, but in a projector-screen pair, it is possible. That is why such a variety of not only projectors but also screens is produced.
By the way, it has always been this way, but previously the circulation of screens produced was relatively small, as was the number of projectors themselves, so they were quite impressive in price and perceived by most as exotic. However, today, thanks to the efforts of Chinese manufacturers, screen prices have fallen so much that some models are now cheaper than a trip to the grocery supermarket, and an incredible number of models have appeared. This, on the one hand, is good, but on the other hand, it has become even easier to make a mistake — there is no longer that restraining factor of high price that makes you think seven times. After all, there are both universal models and highly specialized ones that can help in one situation, and in another — ruin everything possible.
Therefore, the best strategy will not be a detailed study of all types of projection screens, but an understanding of basic characteristics and principles using entry-level examples.
The task defines the type
So, first of all, you need to decide not on the type of surface, materials, or other characteristics, but on the screen configuration. Let's say you need to conduct presentations or simply organize viewing of videos or movies. If you plan to do this in different places, far apart from each other, and also need to quickly organize the process, then the best choice would be a mobile folding tripod screen. For example, Lumien Eco View.
In this model, the screen canvas rolls into a compact tube, which is rigidly attached to the tripod and, when unfolded, stretches, providing a flat surface. Such a screen can be assembled in literally three minutes.
But such a structure should not be taken on a picnic — it is unstable on grass, has excellent windage, and it is quite difficult to securely fasten a single tripod. For any outdoor shows, a screen with a lighter nylon canvas, stretched on a collapsible frame and two stands, is optimal. For example, a model like Lumien Sky View.
Assembling such a structure will take a little longer, but it is almost weightless, and when disassembled, it easily fits into a small bag and can be carried from place to place. The two stands are much more stable, and the screen can be additionally secured with special anchors and guy ropes that come in the kit. It is convenient that, if necessary, the collapsible screen frame can be easily hung on any wall. When used indoors, such a nylon screen is quite comparable to classic white matte models.
If presentations and movie watching are planned in one place, then a stationary screen with an electric drive is preferable, where the motor rolls the canvas into a compact tube located at the top. More and more affordable options for such screens are now appearing.
Especially if the diagonal is large, for example, over 100 inches (width more than 220 cm) — the servo drive will prevent the appearance of canvas stretches, which often occur due to uneven efforts during manual unfolding. The choice of stationary screens with a drive is huge. There are options for wall mounting, ceiling mounting, with the possibility of hidden installation, where only a slit is visible on the ceiling, with special screen canvas tensioners that give it a perfectly flat surface... One of the most inexpensive options is, again, Lumien, but from the Master Control series.
About sizes
Actually, the screen diagonal is calculated based on the projector's capabilities, namely its brightness, or rather, luminous flux. At the same time, it is usually assumed that the room is darkened, there is additional suppression of stray light, which is not the case for presentations in schools, bright meeting rooms, and for many at home and in the country. Therefore, as a first approximation, it makes sense to give some advice for choosing the right screen.
First, the screen size is determined by needs, but with common sense in mind. For example, for presentations in small meeting rooms or classrooms, a screen smaller than 80 inches diagonally should not be used — nothing will be visible from the back rows, but a screen larger than 110 inches is also not needed for these purposes. Another example is a screen for an LED projector. Due to the low actual brightness of such projectors, ideally, a very small screen should be paired with them, but this should not be done — the very meaning of using a projector is lost, because it is needed to create the scale of a big movie. Therefore, it is better to count on buying an 80-inch model, but with a non-standard coating, which I will discuss in detail a little later.
Secondly, the screen size is determined in accordance with the dimensions of the room in which the projection will take place. The projector can be changed in an extreme case, but it will not be possible to install a screen larger than the room allows. And here it is necessary to take into account a more important characteristic of the projector than its brightness — projection ratio. This is the ratio of the distance from the projector to the screen to the width of the resulting image. This parameter, of course, varies for different projectors, but most standard models have a range within 1.4–1.6. At the same time, the larger parameter is critical, because when it is relatively small, the placement problem is solved quite easily — the projector is placed closer to the screen. To avoid delving too deeply into calculations, let's give an example for a typical apartment. If the distance to your screen is 3 m, then the screen width should be approximately 2 m, and the diagonal — 90 inches for a typical wide screen with a 16:9 aspect ratio.
And one more principle. It concerns screens for really large rooms, say, with an area of 80–150 m2. In such spaces, many people want to hang a proportionally large, that is, huge screen with a diagonal of 160 inches (3.5 m wide) and more. It will look harmonious, but it will require a very powerful projector. Even a device with a luminous flux (brightness) of 6000–7000 lm will be too small for such a screen — the picture will turn out frankly dark. This is because the projector's brightness must increase not proportionally to the increase in diagonal, but to the area! That is, by increasing the diagonal by 1.5 times, the projector's brightness must increase by 2.2 times.
At the same time, it is not worth getting carried away with high brightness by buying a projector "with a margin" — the picture will turn out overexposed, that is, pale, low-contrast with a complete absence of dark details.
If it so happened that such a bright projector has already been purchased, and the corresponding large screen cannot be installed, then as an option you can purchase a smaller screen, but with a different type of canvas — the so-called high-contrast (High Contrast), popularly defined as "gray".
Surface selection
Only after determining the configuration and suitable size of the projection screen, you need to choose the type of canvas on which the image will be projected. The most common option is white matte, or Matte White. This type of canvas is used on the absolute majority of screens in the world and is considered universal. However, and it is very important to understand this, this type of canvas will work ideally only in optimal projection conditions, that is, with complete darkening of the room and, very preferably, with dark walls and ceiling. Because an ideally white canvas will inevitably reflect any light hitting it well — not only the projector's beam itself, but also stray light from the entire environment.
Thus, in a bright room with translucent curtains on a white screen, even in combination with the best projector, which has deep black according to tests, this very deep black will not be present in the image at all, only gray instead of black. If this room is also flooded with sunlight or bright lamps, then even the brightest projector in it on a white screen will not be able to create even a somewhat contrasting image.
Here, the reader may probably think that in this scenario, using a projector becomes problematic at all, but it is precisely for such cases that various modifications of ALR screens are developed. For example, the high-contrast reflective (HCR) canvas from Lumien, which we have repeatedly mentioned.
The HCR canvas looks gray, and quite dark, but when an image is projected onto it, the white color in the picture will be quite pronounced, and quite bright, especially if the projector has a sufficient margin of luminous flux. Everything is also fine with the other colors; the dark shades are pleasantly pleasing.
It is important to note here that the reader should not confuse ordinary "gray" High Contrast screens (with a reflection coefficient of ~0.8) with High Contrast Reflective (HCR) screens (with a reflection coefficient of up to 2.5). The former are designed to work with relatively powerful projectors that provide sufficient brightness for projection on a gray canvas, and remain quite versatile, given the wide viewing angle - similar to white screens, they are suitable for use in front of a large audience. ALR/HCR canvas can work perfectly even with budget LED models, in the range of 200-1000 lumens, but requires correct placement of the projector and viewers relative to the screen, with a fairly narrow viewing angle.
An ALR/HCR screen, such as the Lumien Sky Cinema we tested, will be a salvation in bright rooms and will allow a normal picture to be projected even during the day. It also looks gray, but not because it absorbs excess brightness, but because it redirects light in a special way. Its surface has microscopic volumetric facets, arranged according to the principle of a Fresnel lens.
Some of these facets, like a mirror, direct the projector's light to the viewer, while other sides deflect light from walls, lamps, and the sun to the sides. The effect is amazing!
But it only works if you look at the screen strictly perpendicularly — when viewed at a different angle, all the magic disappears. The projector also needs to be placed perpendicularly to such a screen, but it will not interfere with viewers, since the absolute majority of models have a so-called upward projection — the beam exits the lens at an angle, but without image distortion.
There is another nuance. When buying, it is important not to confuse such a reflective screen (ALR/HCR) with ALR canvases for ultra-short throw (UST) projectors. On their surface, the facets are arranged differently and only work if the projector shines from below at a very acute angle. With ordinary projectors, they only worsen the image.
Naturally, this article does not list all types of screens. There are, for example, different types of acoustically transparent canvases for home theaters, which also have their nuances. There are many professional tensioned stationary screens, on various frame structures. And there are also many roll-up screens — this is a very extensive topic. But the main thing is that users now have access to projection technology at a very reasonable price and have the opportunity to enjoy a truly large and high-quality picture in any conditions, both at home and outside.