http://www.camelotherald.com/more/762.shtml
Q: How come my applied tincture isn’t working? Is this a bug?
A: Nope! See if this makes sense – there are three different sorts of tinctures that an alchemist can make and apply. Reactive, volatile, and stable tinctures all have different purposes.
Reactive – these are applied to armor worn on the head, torso, arms, hands, legs, or feet. When you are hit in one of those areas, this tincture’s effect has a chance of going off. These do not work when applied to weapons or shields. A reactive tincture is a defensive measure.
Volatile – there are applied to weapons and shields, and have a chance of going off when the weapon or shield scores a hit of some kinds. The shield tincture won’t go off when the shield is used to block. A volatile tincture is used as an offensive technique.
e ancora:
http://www.camelotherald.com/more/2404.shtml
Q: Reactive tinctures on shields, do they really work? I put a level 43 reactive DD on a lvl 51 shield and went to test it in a task dungeon with my level 45 Hero. About a quarter way through, estimated over 300 blocks, and the proc NEVER went off.
Is there something about blocking where it isn't considered a hit to the shield, thus a reactive proc would not work?
A: Reactive tinctures aren’t meant to work on shields, say both the head of testing and Zimm: “Reactives will not work on shields, only armor pieces. Only offensive procs will work on player made shields.”