Which color range is used for color assessment by visual comparison with a color disk?

Which color range is used for color assessment by visual comparison with a color disk?

• A. greenish-grey
• B. green to brown
• C. yellow to brown
• D. orange to brown

Answer: (C)

When you assess water color by comparing it to a color disk, you rely on a reference that spans from pale yellow to brown. This range matches the colors most natural waters exhibit as dissolved organic matter and minerals impart hues from light yellow to deep brown. The disk provides a clear, consistent gradient for the eye to match, making color estimation more reliable. Greenish-grey or green-to-brown introduce greens that aren’t typical for standard color references, and orange-to-brown focuses on a different, less general hue. Those options don’t align with the common reference scale, so yellow to brown is the appropriate range.

When you assess water color by comparing it to a color disk, you rely on a reference that spans from pale yellow to brown. This range matches the colors most natural waters exhibit as dissolved organic matter and minerals impart hues from light yellow to deep brown. The disk provides a clear, consistent gradient for the eye to match, making color estimation more reliable. Greenish-grey or green-to-brown introduce greens that aren’t typical for standard color references, and orange-to-brown focuses on a different, less general hue. Those options don’t align with the common reference scale, so yellow to brown is the appropriate range.