The 3×3 competency model
All assessments measure performance on three colour dimensions (hue, lightness, chroma) and three competency layers (discrimination, attribution, communication). Together these nine cells form your colour profile.
| Discrimination | Attribution | Communication | |
|---|---|---|---|
| Hue | Can you see the difference? | Can you determine what differs? | Can you name it correctly? |
| Lightness | Can you see the difference? | Can you determine what differs? | Can you name it correctly? |
| Chroma | Can you see the difference? | Can you determine what differs? | Can you name it correctly? |
Diagnostic assessments
Diagnostics measure your current ability without corrective feedback. The score must be reproducible and comparable between baseline and retest.
Hue Ordering Diagnostic
You arrange 90 colour caps (5 segments × 18 caps) in a continuous hue circle. The system measures how accurately you can distinguish hue transitions. The error formula is based on the FM100 (Farnsworth, 1957): for each cap, the absolute difference is calculated between the position of the neighbours and the placed position. The summed error scores form the Total Error Score (TES). Norming takes place via √TES transformation according to Kinnear & Sahraie (2002).
What is measured:
- Total Error Score (TES)
- Error pattern per hue zone (polar error distribution)
- Consistency index (repeatability)
- Pacing score (tempo indication)
Lightness Ordering Diagnostic
You arrange grey values from light to dark. The system measures whether you can correctly rank lightness differences. Lightness discrimination is the most challenging axis for many professionals, because subtle shifts in grey values are less noticeable than hue or chroma differences.
What is measured:
- Ordering error per step
- Error severity (degree of deviation)
- Consistency on retest
Chroma Ordering Diagnostic
You arrange samples from neutral to saturated. This measures your ability to distinguish chroma differences — how well can you perceive gradations in saturation? Chroma discrimination is essential in paint production, textiles and pre-press among others.
What is measured:
- Ordering error per sample
- Chroma sensitivity per hue axis
- Consistency index
Chroma Threshold Diagnostic
A 2AFC forced-choice test with adaptive staircase that determines your chroma threshold: how small can the saturation difference be before you can no longer see it? The staircase automatically adjusts the stimulus intensity based on your responses, in accordance with ASTM E1499-16 §6.3.2.
What is measured:
- Chroma threshold (ΔC at 75% correct)
- Threshold per hue axis
- Confidence interval
Attribution Exercise
You see two colour samples and must determine which colour dimension differs: hue, lightness or chroma — and in which direction. This measures whether you can not only see that there is a difference, but also correctly determine what exactly is changing. This is the key competency that is missing from most classic colour perception tests.
What is measured:
- Attribution accuracy per dimension
- Directional accuracy (warmer/cooler, lighter/darker, more/less saturated)
- Confusion pattern (which dimensions are swapped)
Communication Exercise
You name colours from colour samples and choose colour samples for colour names. This measures the linguistic-professional layer: can you consistently and unambiguously name colour differences within a professional workflow? Based on: Lin, Luo, MacDonald & Tarrant (2001a/b/c) on categorical colour naming; Berlin & Kay (1969) on universal colour categories.
What is measured:
- Naming accuracy per dimension
- Consistency in word choice
- Communication noise index
Magnitude Scaling
You estimate the perceived magnitude of colour differences on a ratio scale, in accordance with ASTM E1499-16 §6.4. This measures whether you can not only see that there is a difference, but also to what degree. Magnitude scaling provides insight into the perceptual scale function: is the difference you see proportional to the actual colour difference?
What is measured:
- Scale consistency
- Perceptual scale function (linear vs. compression)
- Noise in estimates
Training modules
Training measures development and learnability. Feedback is part of the training process. The visual system learns through targeted attention with feedback to weigh distinctions it previously ignored.
Colour Discrimination Training
Practice your chroma sensitivity with detection exercises from neutral grey, white and black. You train your visual system to notice subtler saturation differences. Targeted attention with feedback is the mechanism — the visual system learns to weigh distinctions it previously ignored.
What is measured:
- Mastery per threshold level
- Improvement (improvementDelta)
- Retention (maintained over time)
Scoring formula
Diagnostic and training scores use separate formulas to prevent content contamination:
Diagnostic score
totalScore = accuracy × 0.50 + consistency × 0.30 + (100 − patternPenalty) × 0.20
Training score
totalScore = mastery × 0,35 + improvementDelta × 0,25 + retentionScore × 0,20 + consistency × 0,10 + (100 − supportPenalty) × 0,10
Band classification
ColorAptitude reports results at two levels:
Session-total band (one assessment session) — used for the overall result on the certificate.
| Score | Band |
|---|---|
| ≥ 85 | Excellent |
| 65 – 84 | Functional |
| 40 – 64 | Developing |
| < 40 | Reduced |
Per-cell zone (3×3 matrix) — used for the matrix visualisation and development advice. Each cell is classified using a Bayesian posterior (Beta distribution) with a 95% credible interval.
| Posterior θ̂ | Zone |
|---|---|
| > 80, CIlow > 70 | Master |
| > 65, CIlow > 55 | Proficient |
| > 50, CIlow > 40 | Functional |
| > 35, CIlow > 25 | Developing |
| ≤ 35 | Below level |
| CI width > 30 | Uncertain |