正確には「油性だと思って引いてた修正用のラインが実は顔料インクで、全部剥がれてしまってその部分の銅が綺麗に溶けちゃった」ってかんじです(^^;)
しょんぼりですねー。

To be precise, I thought the correction lines I drew were oil-based, but they were actually pigment ink, so they all peeled off, and the copper in that area melted cleanly. (^^;) What a bummer.