Color is a visual property of a substance that results from the selective absorption and reflection of specific wavelengths of visible light. In the context of a Safety Data Sheet (SDS), color is an important physical characteristic that helps in the identification of substances and can provide information about purity, concentration, or chemical changes.
The color of a substance can be influenced by several factors:
The color of a substance is significant in an SDS for several reasons:
Colors in SDSs are typically described using standard terminology:
| Category | Common Descriptors |
|---|---|
| Basic Colors | White, black, red, blue, green, yellow, orange, purple, brown, gray |
| Modifiers | Light, dark, pale, deep, bright, dull, vivid |
| Combinations | Yellowish-green, reddish-brown, bluish-gray |
| Transparency | Clear, transparent, translucent, opaque |
| Metallic | Silver, gold, copper, bronze, metallic |
| Special Terms | Colorless, off-white, amber, ivory, beige, tan |
Certain colors can be associated with specific chemical properties or hazards:
| Color | Potential Chemical Significance |
|---|---|
| Yellow | Often associated with oxidizing agents, chromates, or nitro compounds |
| Orange-Red | May indicate dichromates, certain metal oxides, or organic dyes |
| Purple | Common in permanganates, iodine solutions, or certain transition metal complexes |
| Green | Often seen in copper compounds, nickel salts, or chromium(III) compounds |
| Blue | Typical of copper(II) compounds, cobalt salts, or certain indicators |
| Brown | May indicate iron(III) compounds, iodine, or certain organic materials |
| Black | Common in carbon-based materials, metal oxides, or sulfides |
| White | Often seen in many inorganic salts, oxides, or pure organic compounds |
Changes in color can be important safety indicators:
According to GHS and various regional regulations (EU CLP, US OSHA HazCom, etc.), the color of a substance or mixture should be indicated in Section 9 of the Safety Data Sheet as part of the description of basic physical and chemical properties. While not always mandatory, it is considered a standard practice for comprehensive hazard communication.
When describing color in an SDS:
