GretagMacbeth ColorChecker DataGretagMacbeth ColorChecker Data
The GretagMacbeth ColorChecker "Color Rendition Chart" is a chart that measures approximately 13 inches by 9 inches (330 mm by 230 mm). It contains 24 colored patches arranged in a 6 by 4 array.
The chart is described in this paper:
McCamy, C.S., Marcus, H., and Davidson, J.G., "A Color Rendition Chart," Journal of Applied Photographic Engineering 11(3) (Summer issue, 1976), 95-99.
The image above is taken from Gretag's page; its RGB values aren't to be trusted. (For example, the grayscale series has a noticeable purple tinge.) Contact me if you'd like accurate RGB values (contact details are on my home page).
Apparently no official spectral reflectance data is available for the ColorChecker. (Spectral data is however available from Gretag for its big brother, the ColorChecker DC.) The ColorChecker used to come with an insert sheet containing colorimetric data, referenced to Illuminant C. I have entered, checked, and double-checked the data on that sheet. The Hue, Value, and Chroma columns are in Munsell notation. (I made a minor editorial change: I indicate Munsell chroma value of zero for the grayscale patches.)
| No | Name | CIE_x | CIE_y | CIE_Y | Hue | Value | Chroma | ISCC_NBS_Name |
| 1 | dark skin | 0.400 | 0.350 | 10.1 | 3 YR | 3.7 | 3.2 | moderate brown |
| 2 | light skin | 0.377 | 0.345 | 35.8 | 2.2 YR | 6.47 | 4.1 | light reddish brown |
| 3 | blue sky | 0.247 | 0.251 | 19.3 | 4.3 PB | 4.95 | 5.5 | moderate blue |
| 4 | foliage | 0.337 | 0.422 | 13.3 | 6.7 GY | 4.2 | 4.1 | moderate olive green |
| 5 | blue flower | 0.265 | 0.240 | 24.3 | 9.7 PB | 5.47 | 6.7 | light violet |
| 6 | bluish green | 0.261 | 0.343 | 43.1 | 2.5 BG | 7 | 6 | light bluish green |
| 7 | orange | 0.506 | 0.407 | 30.1 | 5 YR | 6 | 11 | strong orange |
| 8 | purplish blue | 0.211 | 0.175 | 12.0 | 7.5 PB | 4 | 10.7 | strong purplish blue |
| 9 | moderate red | 0.453 | 0.306 | 19.8 | 2.5 R | 5 | 10 | moderate red |
| 10 | purple | 0.285 | 0.202 | 6.6 | 5 P | 3 | 7 | deep purple |
| 11 | yellow green | 0.380 | 0.489 | 44.3 | 5 GY | 7.1 | 9.1 | strong yellow green |
| 12 | orange yellow | 0.473 | 0.438 | 43.1 | 10 YR | 7 | 10.5 | strong orange yellow |
| 13 | blue | 0.187 | 0.129 | 6.1 | 7.5 PB | 2.9 | 12.7 | vivid purplish blue |
| 14 | green | 0.305 | 0.478 | 23.4 | 0.25 G | 5.4 | 8.65 | strong yellowish green |
| 15 | red | 0.539 | 0.313 | 12.0 | 5 R | 4 | 12 | strong red |
| 16 | yellow | 0.448 | 0.470 | 59.1 | 5 Y | 8 | 11.1 | vivid yellow |
| 17 | magenta | 0.364 | 0.233 | 19.8 | 2.5 RP | 5 | 12 | strong reddish purple |
| 18 | cyan | 0.196 | 0.252 | 19.8 | 5 B | 5 | 8 | strong greenish blue |
| 19 | white | 0.310 | 0.316 | 90.0 | N | 9.5 | 0 | white |
| 20 | neutral 8 | 0.310 | 0.316 | 59.1 | N | 8 | 0 | light gray |
| 21 | neutral 6.5 | 0.310 | 0.316 | 36.2 | N | 6.5 | 0 | light medium gray |
| 22 | neutral 5 | 0.310 | 0.316 | 19.8 | N | 5 | 0 | medium gray |
| 23 | neutral 3.5 | 0.310 | 0.316 | 9.0 | N | 3.5 | 0 | dark gray |
| 24 | black | 0.310 | 0.316 | 3.1 | N | 2 | 0 | black |
You can access the table in tab-separated-value (tsv) format (1414 bytes). If you import this file to Excel (v.X, at least), it will silently take the Munsell hue "5 P" of purple and replace it with 5:00 PM or 17:00:00 or some such (!), and it will silently delete trailing zeros in numeric quantities.
Macbeth was once its own company; it was acquired by Kollmorgen Corporation, which was (I guess) acquired by Gretag, who then started calling themselves GretagMacbeth (spelled all in one word). ColorChecker is also one word (not Color Checker, and not Colour Checker). Macbeth does not have a capital B.