Rigid collodion is a cheap and effective way to produce scarring. The brand I generally use is Mehron. Collodion is applied straight to the skin and then it gently constricts as it dries, tightening the surrounding skin, producing an indented scar. It can be applied to clean skin, or over a colour depending on the desired effect.
In recent years, collodion has been used by many make up artists as a cheap way of reproducing the Joker’s scars (Mehron Rigid Collodion is £3.66 for 25fl.oz.) However, on closer inspection, the Joker’s scars are a mixture of hypertrophic (raised) and atrophic (indented) scars. Collodion can only do atrophic. A minor point perhaps, but I like to be a bit geeky sometimes.
As effective as rigid collodion is, it does have a downside. It’s extremely flammable and can also irritate skin. I have personally experienced this irritation after dressing as the Corpse Bride for a Halloween party. The next day my skin was itchy and red and I still had marks around my mouth, despite peeling the collodion off several hours earlier.
Despite this, I haven’t been put off using it again; my skin is extremely sensitive anyway. I have used it on various different people, skin types etc. and I’m the only one I know who has reacted from it. Perhaps I’m just unlucky.