A matte acid copper plating additive formulated for plating baths with high throwing power resulting in excellent surface to hole thickness ratios in through-hole plating of printed circuit boards. Based on economical copper sulfate and sulfuric acid, it is easy to make up, operate and control. CuBrite CF-110is a single grain refining agent that is added on an ampere hour basis and is notremoved by circulation of the plating solution through afilter packed with carbon. The addition agent reaction products and organic contamination can thus be removed on a continuous basis to assure excellent deposit ductility. CuBrite CF-110produces fine-grained, soft, matte deposits that insure good solderability, resist adhesion and etch characteristics.