The OCS ID System
Every OCS color is identified by a compact string that encodes its full perceptual identity. No lookup table needed—the ID is the specification.
Format
An OCS ID follows this pattern:
OCS-LLCC-HHH-S OCS = Standard prefix (always "OCS") LL = Lightness (00-99) CC = Chroma (00-150, zero-padded) HHH = Hue angle (000-359) S = Substrate code (single letter)
Example Breakdown
OCS-7055-025-C
| 70 | Lightness | 70% perceived brightness on a 0–100 scale |
| 55 | Chroma | Moderate-high color saturation (0 = grey, 150 = most vivid) |
| 025 | Hue | 25° on the hue wheel (red-orange region) |
| C | Substrate | Coated paper stock |
Substrate Codes
| Code | Substrate | Description |
|---|---|---|
C | Coated | Smooth coated paper. The reference substrate. |
U | Uncoated | Uncoated paper stock. Ink absorbs into fibers. |
S | Screen | Digital display (sRGB emitted light). |
T | Textile | Woven fabric. Dye absorption varies with weave. |
P | Plastic | Injection-molded or extruded plastic. |
F | Film | Transparent/translucent film for backlit use. |
Validation
A valid OCS ID must match the regex: /^OCS-\d{2}\d{2,3}-\d{3}-[CUSTPF]$/
IDs are case-sensitive. The prefix is always uppercase OCS and the substrate code is always a single uppercase letter.