When extracting with ethanol a light and more yellow color means an absence of chlorophyll and other plant parts. These experiments were carried out on Cannabis. In many types of Cannabis extracts, such as oil for medication, chlorophyll is undesirable.
The image above represents three different extractions. One done at -5 degrees Celsius, one at room temperature and one at elevated temperatures. The image pretty much speaks for itself.
The amber color ethanol was produced using Frankenstein.