How to improve color of copper on MIG wire , process is electrolysis of copper sulphate

I am Lecturer in Chemical Engineering, doing project on improving the color of the copper coating on the MIG wire. The process used is Cleaning ( by 10 % Sulfuric Acid ) -> DM Water Cleaning -> Dipping in copper sulphate ⇦ on eBay or Amazon [affil link] Sol -> DM Water Cleaning -> sodium carbonate ⇦ on eBay or Amazon] ( 1% ) dipping . We have tried to improve the surface finish by changing concentration of copper sulphate , Temp etc. Only thing left is to test by changing the reducing agent , we tested by increasing the concentration of sodium carbonate, and some improvement is observed. Can we use some other reducing agent instead of Sod carbonate, or any other remedy ?

We are manufacturing CO2 Welding Wire. There are commercial brighteners available, which if added to the CuSO4+H2SO4 Solution brightens the colour. However, the final tank in the process, which consists of stearate based alkaline solution also acting as a wire drawing lubricant for the finishing pass after the copper coating, is normally enough.