Table 1 National bureau of standards ratings
National Bureau of Standards units | Description of color change |
|---|---|
0.0–0.5 | Trace: extremely slight change |
0.5–1.5 | Slight: slight change |
1.5–3.0 | Noticeable: perceivable |
3.0–6.0 | Appreciable: marked change |
6.0–12.0 | Much: extremely marked change |
12.0 and more | Very much: change to other color |