I got called in to do sp/fx (that's "industry" for special effect makeup) the day before a shoot when the regular sp/fx guy had an emergency and couldn't make it. The makeup guy called me and asked if I could step in for him, since we've worked together before and I could keep continuity with his work.
The script called for the actor, in a state of mental anguish, to torture herself by pressing a razor blade into her palm. Not to slice it up a lot, just a little. Since this was being shot with hi-def equipment the cut had to look like a real cut, which meant thin layers.
I would have preferred to create a silicone appliance that she could actually slash up, put a little blood pack beneath it so they could shoot it all in one, but there was no time for that luxury. So I relied on the lo-tech old school method of latex, paint, and runny blood, and great acting, and we got it in one take.
I don't have access to the footage, as it's still in post production. The effect was so realistic that the producer, who was watching on the monitor, turned a funny shade of green and had to take some deep breaths before the cold sweats went away. So, not for the squeamish!
Step 1: Materials Needed & Preparation
Injury Stack Greasepaints
Small Palette Knife
Small Palette or Disposable Non-paper Plate
Runny Stage Blood
Small Paint Brushes (2)
Witch Hazel or Other Oil-Free Toner
Small Glass or Metal Bowl
If you don't have an injury stack or injury wheel, you can use greasepaints in red and black. If your trauma needs a little bruising, you'll also want blue and yellow paints, or a bruise wheel.
Begin by cleansing the area with toner to remove any excess oils and perspiration.