CRI is a colour rendering cue for how light affects the appearance of surfaces.
CRI, also called Ra in many lighting contexts, is a colour rendering index. It should be read beside CCT, lumens, beam spread and the task surface.
Technical meaning
CRI is a colour rendering index that describes how a light source affects the appearance of colours compared with a defined comparator.
Ra is the general CRI value commonly shown in lighting data, while more detailed rendering information may be needed for colour-critical tasks.
Calculation use
CRI records a rendering assumption beside lux, lumen and CCT notes when a task depends on colour judgement.
CRI can help separate general ambient lighting from areas where finishes, food, artwork, retail displays or inspection work need better colour appearance.
Not the same as
CRI is not brightness. A higher CRI value does not mean more lumens or higher lux.
CRI is not a complete quality score by itself. CCT, spectrum, glare, beam control, flicker and task conditions can still change the result.
Australian context
Australian education, retail, hospitality and task-lighting notes should record CRI as one rendering cue rather than a substitute for the full lighting brief.
Examples
Example
Value
Planning note
Basic utility area
CRI 80+
Often adequate for general movement and storage when colour judgement is not the main task.
Customer-facing interior
CRI 90+
Can improve surface and merchandise appearance, while output and CCT still need separate checks.
Colour-critical work
Beyond Ra only
May need fuller rendering data and project review rather than a single CRI number.