Silver PETG prints - base layer print lines showing

Bambu Lab X Series Troubleshooting
1

I printed of a small rectangular plate in silver PETG, and noticed that the part surface shows the first layer lines, as if it was done in a jean material, even if the surface is smooth to the finger

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I printed the exact same model in gray and the lines are invisible

  • Printer model used : X1c, with engineering plate
  • Slicer settings used : generic PETG / PETG HF, the model is printed flat, to get a smooth finish
  • Type of filament used : Tinmorry metallic silver PETG

side by side prints using the same 3mf file, left and center parts are printed using silver PETG, right part is printed using BBL PETG HF :

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the best result (center) was achieved by printing the part the other way round, (flat on top) and using additional ironing

I think part of the problem comes from the metallic material reflectiveness showing more those lines, but I’d like to lower the variation next to the limits of the parts
could pressure advance adjustment bring some better results ?
other ideas welcome

thanks