sentences:  The process for electroplating platinum black on platinum was invented by Lummer and Kurlbaum when they were unable to reproduce Langley's lampblack-covered platinum foils for bolometers.When the platinum black did not adhere to the cathode, they found that adding around 1% copper sulfate to the chloroplatinic acid in the electrolyte improved the results.Later, they found a much smaller proportion of lead acetate worked better than the copper sulfate.