A very dark brown deposit of gold from an electro-gilding bath is generally caused by excess of current, but may also be due to excessive free cyanide and to a deficiency of gold in the solution. The current may be reduced either by employing a resistance coil or by reducing the battery power. Excessive free cyanide may be reduced by dissolving more gold in the bath, or by adding cyanide of gold until the excess cyanide of potassium has been taken up.