1)indelible ink,Silver nitrate ink 2)Electoral finger staining,can't be easily washed off 3)violet to black,used for election

1)Indelible ink,Silver nitrate ink2)Electoral finger staining,can't be easily washed off3)violet to black color,used for election

4)also called silver nitrate ink,since it can't be washed by water ,it mostly yo be used for voting and election,the content of the silver nitrate could be 5%,10%,15%,25%....... according to your require,and the more content of silver nitrate contain,the better effect it will be .