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 It's here: the Cine4Home BlackScreen by Maxlum
From the experimental project to the finished product:
High-contrast projection in living rooms has finally become possible
A few months ago, we mentioned a new project regarding a new approach to daylight projection in our last special report. Instead of being blinded by increasingly higher amounts of light and gain screens with all their disadvantages and still foregoing a good black level, we experimented with dark material that allows for a good black level in non-darkened rooms.
In that special report we announced our intention to pursue the subject further and look for partners to implement this innovative approach. It took a while, but we now have our first results: the motorised manual screen, "BlackScreen", 2m wide. This was made possible by a cooperation between several companies. The BlackScreen will be produced in high quality in Europe.
In several special reports, we will examine how far the model corresponds to our perceptions, where the advantages and disadvantages are and how it should be implemented correctly. This week we begin by presenting the product, the first pictures and a compact explanation of functions. Next week we will show you a detailed video documentation from Grobi, the large-screen specialist. Then in several tests we will establish the best projectors in all price ranges. Initial tests have shown that there is a growing number of affordable compatible models on the projector market.
Where is the black?
Anyone who has ever devoted their time to the subject of large-screen projection and home cinema knows what the problem is - the age old enemy of projected images is ambient light. If you want to project an image in a darkened room, you will come across the main phenomena, that there is no “black”. Black is the absence of light, so you cannot project it. But in a bright room there is no absence of light. The darkest thing you can therfore produce on the screen is the brightness of the screen when the projector is turned off, and that is usually white. Even small sources of light can mar the black level and therefore the contrast and image depth. So it is unimaginable to project in a darkened room.
There are no shadows when it is very bright!
To deceive the eye, a lot of projectors resort to extremely high light output. They then end up trying to conquer the sunlight with even more light to deceive the human eye so that the basic white colour of the canvas screen still appears black as the rest of the projected image is much brighter. The light from the projector adds to the basic brightness of the room and the screen.
Despite the black level being lightened by ambient light, a certain contrast level can still be provided with a particularly high white level
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This principle at least works when it comes to images that contain a lot of light elements, such as daylight scenes. If you prefer to watch sports broadcasts regardless of the quality of the image rather than films, you can revert to this method.
Even bright images with a very high light output can be projected in non-darkened rooms
But the problems are much larger if you want to project images with a weak contrast but with a high level of black, e.g. night scenes. Images such as these have no bright elements that dazzle your eyes, making other parts appear black.
Dark images do not provide high contrast
During the day it is light and not dark and this is what ruins the night scene in the example above. You cannot see anything on the screen, just the white canvas. However, since many films are often set in the dark or semi-darkness, they cannot be projected properly.
Without strong contrasts the projected image suffers terribly from ambient light conditions
Screens with a high Gain factor do provide an improvement. They do not scatter the light evenly in all directions, but they collect it as a sort of parabolic mirror in the centre of the potential viewing angle. The light output of the projector therefore increases because of better use and the "dazzling" effect described above also increases. At the same time, a high-quality Gain screen does not reflect oblique light, and so reduces the basic brightness in black areas.
Gain screens (right) increase the perceptible contrast
Bright images therefore become more appealing. The basic problem of shooting at night, without strong contrasts, however, still exists, albeit in a weakened form, as the basic colour of a Gain screen is also quite light and cannot produce any black. Additionally, the limited viewing angle is also a problem. Because of the concentration of light, you cannot see any images from oblique angles as it is simply not reflected there!
Compared to a conventional screen (left) the gain screen concentrates more in the direction of the direct viewer (right)
Also, the phenomenon of "hotspots" arises. The surface of the screen does not illuminate completely evenly, but is significantly brighter in the middle than in the edges or corners.
Gain screens often appear brighter in the middle than in the peripheral areas. The illumination is affected negatively
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All this makes daylight projection with Gain screens more or less compromise-ridden and does not meet any high-end demands. Moreover, these additional restrictions on hotspots and viewing angles also apply to darkened rooms, so that even in the evening in a darkened home cinema only moderate image results with Gain screens can be achieved. Given the high prices of such screens for home cinemas, this solution is not really recommendable.
Black is beautiful!
The Cine4Home BlackScreen ensures optimal black levels and maximum contrast. The problem in non-darkened rooms is the black level. Black is not dark on conventional screens, but white.
How can this problem be solved?
To start with, let’s take a look at traditional TVs or computer monitors. They don’t have a problem in bright living rooms in showing dark images with a high proportion of black. Black appears really dark. So how can this be possible? The answer to this question is simple: the monitors are not bright or even white when turned off but dark grey or black. A black cathode ray tube allows for a high basic contrast. The principle is also the same for current flat-screen TVs with LCD or plasma technology - when turned off they are as dark as possible. The darker the basic state is, the better the contrast possibilities in bright living rooms.
This simple approach was used for the new Cine4Home BlackScreen. Our screen is the image area for large-screen projection. Because of its dark basic colour, it allows, just like plasma TVs, a consistently good black level even in non-darkened rooms.
An almost black screen provides a good black level
As this special projection fabric absorbs a certain portion of the amount of light, projectors with high light output are still required. Depending on the size of the image and surrounding ambient light, we recommend projectors with at least 3000 ANSI lumens. Fortunately, nowadays you can find many state of the art compact models at reasonable prices.
Properly installed, the Cine4Home BlackScreen can be used freely regardless of the ambient light. In darkened rooms, the screen improves the black level significantly, so that it really does look dark. The full contrast potential of the projector is used and the presentation is accordingly vivid.
But even in bright rooms, the image quality is good and virtually unchanged. Dark scenes with a high level of black remain appealing, while the light elements remain constantly bright. About 75% of the disturbing stray reflections are absorbed by the dark grey canvas.
Black vs. white
The Cine4Home BlackScreen does make it possible: high-contrast projection in non-darkened rooms! The advantages over conventional Gain screens are numerous:
• Improved black level
• More contrast
• No unpleasant exaggerated brightness in daylight scenes
• No limited viewing angle
• No hotspots
The dark grey screen behaves just like a traditional matt white screen, it diffuses the projected image equally in all directions.
Advantages even in darkened rooms: higher ANSI contrast despite white walls!
A major advantage of the BlackScreen is that it is also beneficial when used in darkened rooms. Here it works miracles in as far as that it enables an ANSI contrast ratio of over 200 in completely white living rooms. In comparison, a white screen in traditional living rooms only allows an ANSI contrast ratio of approximately 50:1.
The first field test
After the first model was delivered, we put it up in one of our test studios. Compared to our conventional fixed frame screen, the difference became obvious quickly:
The BlackScreen has a good contrast compared to our conventional screen
The width of the canvas is determined by the current light output possibilities of the projector. The BlackSreen is 2m wide and suitable for most applications and compared to a conventional flat TV extremely huge. As you can see in the picture above, the canvas can be used very well to complement an existing screen: BlackScreen during the day, the standard screen in the evening.
We used a Full HD projector from the professional range with a light output of (net) 4500 lumens. We brightened our test room by opening all of our dark curtains and exposing the windows. It was especially difficult as the sun was shining directly onto the outer part of the screen, as can be seen in the picture above.
For our first test, we simulated various applications with appropriate visual material. Probably the most obvious area for daylight projections are sports broadcasts. Who wants to sit in a dark room to watch football, Formula 1, or a cycling race?
The above photo has not been retouched, but it reflects the actual visual impression on site! Because of the dark basic tone, the contrast seems to be balanced. The maximum light output corresponds to the ambient light and therefore does not appear too dark.
The next common use is video games. Once again, it is difficult to accept a compromise with the darkness if you want to play together with friends.
The example shows that bright colours in many video games come too short. The fun in playing is multiplied by the combination of daylight and extremely larger image size compared to conventional flat TVs!
"Last but not least”, the most critical use has to be tested: feature films. They are often set in the dark and often have a weak contrast, but especially here image depth and black level are most important to create the desired atmosphere.
Again, our projection comes strikingly close to the quality of a good TV. The correct setting of image width, brightness, black level and contrast deliver impressive results in almost every scene. Of particular interest are also the image-improving properties even when the room is completely dark. Stray light from white walls is no longer a problem, since it is filtered by the screen up to 80%. A large part of the projector's native ANSI contrast (> 200:1) is retained, so that for the first time ever this is also of relative importance for living rooms.
You do not need magic to produce such good results. But it is still not that simple (unfortunately). During the installation, you have to first consider the lighting conditions in the room in general, the incident of light on the screen and the demands on the beamer (brightness/contrast) resulting thereof. It quickly becomes clear that there are different solutions to be considered depending on the weighting ... for unfortunately it is not totally without compromises.
In tour next special report we shall therefore essentially deal with the aspects of room planning and will test the first projectors - with the emphasis being on achieving the best possible "hybrid image experience" (both in daylight and in a darkened room).
If you cannot wait for the next report, feel free to contact us directly with your questions:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Your Cine4Home team,
Ekkehart Schmitt www.Cine4Home.com
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