ABL Circuits PCB Manufacture Electrolysis
Here is a panel that has been laminated and exposed and developed. You may be able to see the black carbon down the holes from the shadow process earlier, and that gives the electrical conductivity between the two sides of the board. So the next process is to plate copper over the holes and over the whole panel so that all the copper areas that you can see will be the tracking that you require on your finished circuit board.
The plating process requires clamping the panel onto a jig and passing an electric current through the jig to plate the copper down the holes. The amount of amps required for plating the panel varies on every board and even on each side depending on the amount of copper on the panel. From the photo plots a calculation is done which allows us to calculate the number of amps required for each side so that we get perfect plating.