Why ANSI Contrast?

The easiest way to explain why ANSI contrast is the better way to measure how good the contrast is for a projector, ANSI contrast refers to the difference between black and white when they coexist in the image. In other words very different from setting up a black image, measure, setting up a white image, measure and divide the result on white with the result on black. With ANSI, you measure black and white in the same image together.

What is ANSI Contrast

As mentioned ANSI contrast, is a more representative and accurate parameter for quantifying the contrast ratio, sometimes also called “checkerboard contrast”. In this method, you measure the brightest whites and darkest blacks, but in a setup that is much more representative of how the system will eventually be used in reality and perceived by the audience. The ANSI contrast measurement is also more difficult to cheat on when trying to boost the results. When measuring the ANSI contrast, the pattern on screen is not full-screen white or black, but a 4x4 checkerboard pattern consisting of 8 white and 8 black squares. The black again needs to be the same level as when showing black content: since you are at the same time displaying white squares, playing tricks by dimming the light source will not help as the bright zones will be equally impacted. 
The fact that you project white and black simultaneously on-screen means you take into account reflections and flare of the projector and the room. Light intended for the white squares will find its way and fall onto the black squares where they will raise the light level and reduce the contrast ratio. This is what happens in real content, so the test pattern should reflect the phenomenon. Inside the projector, light scatters in the optical elements and leaves the lens in places where it is not intended to be. This is impacted by the material quality of the glass elements, fringe effect, light absorbers and coatings inside the projector, but also by the inherent light modulating technology used (DMD, LCD, LCOS …). In the end, it relates more to real images as it has white and black in the image at the same time during measurement.

Download our ANSI contrast whitepaper

Here you can download our contrast white paper, where you in more detail can learn the difference between sequential contrast and ANSI contrast.

Downnload the whitepaper here