Troubleshooting: Ink Won't Take on Metal
故障：金属面拓印不上墨
标签：不上墨,油膜,氧化层,打毛,定画
金属光滑面墨附着力差，常因有油膜或氧化层。先用 acetone/酒精彻底去油，再以细砂纸（800#）轻微打毛增附，或先转印复写纸底图再补墨。铜面若已生成厚氧化皮，需先打磨露出基体。
Smooth metal holds little ink due to oil film or oxide. Degrease fully with acetone/alcohol, lightly scuff with 800# paper for grip, or transfer a carbon base first then ink over it. If thick scale exists, sand to bare metal first. ---