1. To check the color vividness of pigment paste; black pigment paste must be black, this black can absorb more light, not gray black color. White pigment paste must be pure white. 2. To confirm the solid content of pigment color paste. It is the color strength that is the key to determine the customer's useing cost. The customer can add the same amount of pigment paste into the same quantity of matched binders, then stirs evenly. It should be known that which kinds of pigment paste has better color strength. The customer can compare them with their own conditions, or can also commission our technical department to do comparative testing. Only by comparing and testing, we can we know the real good quality and real cost. 3. Safey standards of water based pigment paste. Currently, the quality of aqueous pigment pastes on the market is very different. Although they are all called water-based pigment paste, some of lower prices pigment pastes are produced by inferior pigments. Heavy metals and heterocyclic aromatic hydrocarbons will be excessive, there are serious security risks in the applications! so customers must pay attention to the safety quality of water-based pigment paste! 4. Pigment paste quotation list must include the pigment content. Experienced customers would require pigment paste suppliers offer the data of pigment content in pigment paste. Some of pigment paste factories just provide solid content index to the customers, but solid content is not the pigment content. The solid content contains the solid content of other surfactants, but is not equivalent to pigment content. This is also very important.