which color is lighter cognac leather or buttercup leather?

Answer 1

I would think buttercup because buttercup flowers are a lighter yellow than the amber color of cognac liquor.

Answer 2

A company or manufacturer makes up names like those according to what they think sounds good and will help sell their product. There's no way of knowing whether cognac means deep brown or gold or tan without a sample. You need to see a sample or a color chart from the company.