with water in ratios from about 1 part of copper solution to 1 part of rochelle salt solution to 4 parts of water to about 1 part copper solution to 1 part rochelle salt solution to 10 parts of water to provide relatively thick copper coatings suitable for oxidation the preferred dilution ratio is from about 1 1 5 to about 1 1 8 and a dilution ratio of 1 1 6 is most preferred the copper solution is appplied by dripping from a drip pipe as described above for tin application although other application techniques such as spraying pouring or brushing for example might also be conveniently employed following contact of the article with this copper filming composition the article is again rinsed with water and may be dried by air following this the copper film is contacted with an aqueous solution containing an adsorbing surfactant this surfactant solution preferably contains from about 0 05 to 5 percent by weight of surfactant and sorbitan monolaurate is the preferred surfactant the surfactant solution is applied by pouring spraying or dripping and may after a short contact time be rinsed from the plate with a water rinse the article is then dried the coated article is then heated in an oxidizing atmosphere at a temperature above about 300 u00b0 f preferably between about 400 u00b0 to 600 u00b0 f and most preferably about 450 u00b0 f the coated article is maintained at that temperature for a period from about 5 to.