Oct 14, 2014

Choosing the right contrast ratio for your meeting room projector

Corporate and lobby

2 min read

In display technology, contrast is one of the most important image quality metrics. It allows us to distinguish the content of an image regardless of its brightness. And the challenges that come with producing an ideal contrast ratio have forever been a key point of focus for the projection industry.


What is contrast?

The American National Standards Institute (ANSI) defines contrast as ‘the absolute difference in luminance between the peak white and black levels, where white and black luminance is displayed simultaneously.’ Put simply, contrast is the ratio between the full black and the full white in an image. A contrast ratio of 1,000:1 means that the white is a thousand times brighter than the black. In any display system, including projection, the higher the number – the better it is.


Why is contrast important?

Contrast ratio is all about seeing the subtle details in an image. Low contrast means no details. High contrast means a lot of details. Which requirements need to be met in your meeting room? InfoComm created an ANSI standard called Projected Image System Contrast Ratio (PISCR), which defines four levels of contrast based on content viewing requirements:

1) Passive viewing (7:1 contrast ratio)

With a passive viewing ratio, the viewer will be able to recognize the images on a screen and distinguish text readily from the background. However, it does not allow detailed understanding of content. Passive viewing will typically be used with noncritical or informal presentations.

2) Basic decision making (15:1 contrast ratio)

The basic decision making ratio enables the viewer to make simple decisions based on the content displayed on a screen. These decisions do not depend on critical details within the image. This ratio fosters active viewer engagement and is most commonly used in public information displays, presentations containing detailed images, classrooms, and some multi-purpose boardrooms.

3) Analytical decision making (50:1 contrast ratio)

With an analytical decision making ratio, the viewer can make critical decisions based on the ability to analyse in detail the content displayed on screen. This ratio level lends itself to high-engagement, analytical environments, such as medical imaging, architecture, engineering, forensics or professional photography.

4) Full-motion video (80:1 contrast ratio)

A full-motion video ratio allows the viewer to discern key elements of a video sequence, such as vital details provided by the cinematographer or videographer necessary to support the storyline. Full-motion video ratio is, therefore, most common in home theatres, business screening rooms and broadcast post-production settings.
  

How is this important for me?

The ANSI standard blends important aspects such as projector brightness and ambient light in a complete system ratio. If you read our previous blog post, you’ll see how the projector’s brightness level has a direct impact on its contrast ratio. That’s why, when choosing a projector, it’s important to pick one with sufficient brightness!

See our video on contrast for more information and see our Projector Selector as support for your selection!

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