Question

Find the correct statement?

• A. In the CIELAB system, colors are described with three color coordinates L*, a* and b* where Lightness L* goes from 0 (white) to 100 (black), a* is the green‐ yellow axis and b* is the red‐blue axis
• B. In the CIELAB system, colors are described with three color coordinates L*, a* and b* where Lightness L* goes from 0 (black) to 100 (white), a* is the red‐green axis and b* is the yellow‐blue axis.
• C. In the CIELAB system, colors are described with three color coordinates L*, a* and b* where Lightness L* goes from 0 (black) to 100 (white), a* is the yellow‐ red axis and b* is the purple‐blue axis.
• D. In the CIELAB system, colors are described with three color coordinates L*, a* and b* where Lightness L* goes from 0 (white) to 100 (black), a* is the orange‐green axis and b* is the red‐pink axis.

Hint:

Easy Mnemonic for CIELAB:
L = Light ($0$ Dark, $100$ Bright).
a = Apple (Red/Green).
b = Banana (Yellow/Blue).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the correct definition of the parameters used in the CIELAB ($L^*a^*b^*$) color space, which is the most common standard for measuring and describing food color objectively.

Step 2: Detailed Explanation:

• CIELAB Coordinates: The system is based on the "Opponent Color" theory. It uses three coordinates:
- L* (Lightness): Ranges from $0$ (absolute black) to $100$ (pure white).
- a* (Redness/Greenness): This is the red-green axis. Positive values ($+a^*$) are red; negative values ($-a^*$) are green.
- b* (Yellowness/Blueness): This is the yellow-blue axis. Positive values ($+b^*$) are yellow; negative values ($-b^*$) are blue.

• Evaluating Options:
- Option (A) incorrectly claims $L^*$ goes from white to black and maps $a^*$ and $b^*$ to the wrong colors.
- Option (B) correctly identifies $L^*$ range ($0$ Black to $100$ White), the red-green axis ($a^*$), and the yellow-blue axis ($b^*$).
- Options (C) and (D) invent non-existent axis pairs.

Step 3: Final Answer:
The description provided in option (B) is the scientifically correct definition of the CIELAB system.