Modern writing inks usually contain ferrous sulfate with a small amount of an acid; on paper they darken and bond becoming permanent.
现代写字用的墨水通常包括了硫酸亚铁和少量的酸；写在纸上，颜色会越来越深，且能保持永不褪色。
Modern writing inks usually contain ferrous sulfate with a small amount of an acid; on paper they darken and bond becoming permanent.
现代写字用的墨水通常包括了硫酸亚铁和少量的酸；写在纸上，颜色会越来越深，且能保持永不褪色。
应用推荐