Now when we switch to the ANSI checkerboard, we still get 1000 units on the whites, but due to light scatter we might get 0.5 units on the blacks instead of 0.05. That would be a contrast ratio of 20,000:1. For example, let's say our meter tells us that "full on" white on the 100 IRE screen is 1000 units and "full off" black on the 0 IRE screen is 0.05 units. can a bit of light scatter have that much effect on the ultimate contrast ratio? Absolutely. In addition, any dust that happens to be floating in the path of projected light will cause light scatter.īut, you ask. A little bit of that light gets reflected and bounced around inside the zoom lens or light engine and ends up compromising the black rectangles in the projected image. On the other hand, when the checkerboard is being displayed, the picture is 50% white and there is a lot of light being projected. When the projector is displaying a fully black 0 IRE test pattern, there is no light to scatter internally that could compromise the black level. Why is that? First, there is always the potential for light scatter in the projector's light engine and lens when anything other than black is being projected.
#4000 LUX LUMEN COMPARED TO ANSI FULL#
The reason is that, though we usually get similar readings between the white 100 IRE test pattern and the white rectangles on the checkerboard pattern, the black readings on the ANSI checkerboard are always higher than black readings on a full black 0 IRE test pattern. Where projectors are concerned, the Full On/Off and ANSI methods yield radically different numbers, and the ANSI reading is always substantially lower (not even in the same ballpark, actually). The ratio of the averaged white readings to the black readings is the ANSI contrast ratio. The brightness values of all the white squares are measured and averaged, and the brightness of the black squares are measured and averaged. Instead, it uses a single checkerboard pattern of 16 rectangles, eight white and eight black. The ANSI Contrast method does not use the 100 IRE white and 0 IRE black screens. A contrast ratio of 10,000:1 indicates that the meter is reading the white as being ten thousand times brighter than the black. Let's take a look at the difference between them.Ī Full On/Off Contrast reading measures the ratio between the brightness of a solid white, 100 IRE test pattern ("full on"), and the brightness of a solid black, 0 IRE test pattern ("full off"). The ANSI method is difficult to manipulate, produces very small but much more valid and informative numbers, and is rarely used in the industry other than by manufacturers in specialty niches. Full On/Off is easy to manipulate, it produces misleading numbers, and is commonly used in the industry. There are two common methods of measuring contrast - Full On/Off and ANSI Contrast. What is the Best Way to Measure Projector Contrast Ratio?
So good contrast is all about seeing the details. Contrast is what makes it possible for us to see the subtle shades of colors. The higher the contrast ratio, the more detail you can see on the projected image whether it is numbers, pictures, graphs, text, or video. So a projector with a 3000:1 contrast ratio means that the white image is 3000 times brighter than the black image. Who doesn't want a high contrast projector? And manufacturers are well aware of the consumer's sensitivity to contrast specs, so they've had to pump them to absurd levels just to stay competitive.Ĭontrast ratio in its simplest form is the ratio of the light reflected from an all white image and an all black image.
Nevertheless, since buyers usually cannot see and compare projectors before they buy, they get consumed with contrast ratings for obvious reasons. Contrast specs don't tell you much about what you'll see on the screen, and they certainly don't tell you anything about how one projector will look if compared to another side by side. Of all the specs published for projectors, the Full On/Off Contrast spec is the most meaningless and misleading spec on the page.
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