Keeping up Appearances

Yellowing is commonly caused by either the coating formulation or over-cure. Wittig recommends keeping an eye on coating selection, because some yellow more than others. Also consider cure speed: "If you cure a high-speed formulation at a low speed, you could potentially over-cure the product, which will give a yellow appearance right off the press," he affirms. Lowering lamp power at slower speeds may reduce yellowing in such cases.