What is definition of black oil product?

Here is my answer based on crude oil refining economic perspective In the past, black oil & white oil product term has been used to simply differentiate between products that can give more value than crude or not. So happened that most if not all black colored products have less value than crude, hence the term Black Oil was used to make this differentiation. Therefore: Black oil product is simply defined as any refined product that is having less economic value than crude oil per unit (must use equivalent unit) price. -Shahrul IB-