I'm Not Sure Which One I Need

Definition

15:1 Minimum Contrast Ratio

The viewer can make basic decisions from the displayed image. Images and text are legible to the extent that basic decisions can be made

Decisions based on content itself, not resolution of detail Non-analytical viewing

The viewer is actively engaged with the content (e.g., information displays, presentations containing text and images, classrooms, boardrooms, multi-purpose rooms, product illustrations).

50:1 Minimum Contrast Ratio

The viewer can make critical decisions with the ability to analyze details within the displayed image.

The viewer is analytical and fully engaged with the content’s details.

This category requires that the finest detail available in an image is evident down to one line pair (e.g., art history classrooms, medical imaging, architectural/engineering drawings, forensic evidence, image inspection).

Communication Level

Basic information is retained

Line-pair level detail in image not required

Analyze (fine) detail to make critical decisions

Line-pair detail in image is required

Description

Ability to discern elements that are a certain percentage of the overall image height, relative to viewing distance·

Ability to absorb information within time constraints

Based on visual acuity to discern a line pair

Placing as much information on the screen as possible and be able to discern all of the intended detail

Ability to view analytical material for extended period of time

Ability to view analytical material for extended period of time

Comfort not a significant factor

Environment

Typical office environment, meeting rooms, classrooms

Unpredictable ambient light

Possible task lighting

Highly controlled environment

Controlled ambient light

Focused task lighting

No ambient light directly affecting screen, black-out window treatments