Grayscale is used for assessing the color shading in between products and the customer’s approval sample or among pieces in production.
According to the Prop 65 regulation:
“Any person doing business in California who knowingly and intentionally exposes California consumers to one of 900 listed chemicals known to cause cancer or reproductive toxicity must give a “clear and reasonable” warning to those consumers.”
Proposition 65 is the set of laws that require businesses to keep Californians aware of the compositions of their products if they contain certain chemicals that are carcinogenic, cause childbirth anomalies or other harms to the reproductive system of the consumers.
For every product manufactured, whether in batches or not, there is always a need to inspect them, as to whether or not the manufacturers meet the standards set for the product. Most manufacturers mass produce in batches. It would be a big waste of time, money and energy to go through all products one after the other. In fact, it might even be impossible to do so. That is why the AQL was introduced.